samples FKM-101 to FKM-200

 

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Windsor Vermont talc chlorite schist in thin section

sample: FKM-101 (billet from the Univ. Arizona petrology collection, sample Wards 87; this sample is similar to and from the same vicinity as FKM-115)
locality: Chester, Windsor Co., VT, USA.
rock type: talc-chlorite schist. Greenschist facies metabasite.
major mineralogy: Predominately chlorite and talc, with minor apatite and pyrite.
(unpolarized light)

Windsor Vermont talc chlorite schist in thin section

same as previous FKM-101 image (under crossed polars).

 




Custer South Dakota tourmaline schist in thin section

sample: FKM-102 (billet from the Univ. Arizona petrology collection, sample Wards 89)
locality: near Custer, SD, USA.
rock type: microcline-tourmaline-biotite-muscovite schist. Rich in Al, K, (Fe+Mg) and B, but with no chlorite and essentially no quartz or feldspars in the matrix, the mineralogical reflection of the bulk rock chemistry seems unusual for a typical pelitic protolith. It may be possible that the protolith was a metasomatic rock prior to metamorphism, regardless of an original sedimentary or igneous origin.
major mineralogy: The phyllosilicate matrix of this schist is composed of approximately sub-equal amounts of muscovite and Fe-rich biotite. Quartz in the matrix is surprisingly uncommon, and there is no fine-grained plagioclase or K-spar within the matrix. Two distinctive porphyroblast populations are present: metamorphic microcline overgrows scattered “mini-augen” of orthoclase (likely relict), and tourmaline is present oriented both parallel to the long dimension of the thin section and perpendicular to the plane of the thin section (hence appearing to define two roughly perpendicular lineations within the plane of the phyllosilicate foliation). Although the tourmaline exhibits optically distinct rims and cores (the former shows tan to brown pleochroism, while the latter shows grayish-brown to bluish pleochroism), chemical analyses suggest little apparent compositional difference between the cores and rims (however, there possibly may be a significant difference in the Fe2+/Fe3+ ratio; see the below discussion on normalization constraints). Sparse near-end-member albite occurs along the outer edges of a few of the microcline porphyroblasts. Abundant tiny apatite and monazite are scattered in the matrix. For the “core” tourmaline, mathematically permissible values of M3+/∑M (M = Fe+Mn) span from 0.00 to 0.25 (which yield OH/(O+OH) ratios consistent with dravite, but are too Al-rich to normalize to dravite), from 0.25 to 0.33 (which yield OH/(O+OH) ratios consistent with oxy-dravite, but which can not be readily cast into either an oxy-dravite or oxy-schorl formula), and finally from 0.33 to 0.55 (which also yield OH/(O+OH) ratios consistent with oxy-dravite, and can be successfully normalized as such). Values of M3+/∑M above 0.55 are not mathematically permissible, producing non-sensical negative OH/(O+OH) ratios. A similar evaluation can be done for the “rim” tourmaline: in this case, mathematically permissible values of M3+/∑M from 0.00 to 0.18 yield formulas with OH/(O+OH) ratios consistent with dravite and and which can be successfully normalized as such; values between 0.18 and 0.25 also yield OH/(O+OH) ratios consistent with dravite, but simultaneously calculate cation site-fillings more consistent with oxy-dravite; and finally values from 0.25 to 0.44, which yield OH/(O+OH) ratios consistent with oxy-dravite but which again can not be readily cast into either an oxy-dravite or oxy-schorl formula. Analogous to the “core” normalizations, values of M3+/∑M above 0.44 for the “rim” normalizations yield non-sensical negative OH/(O+OH) ratios. The interesting outcome of this calculation is that for the “core” tourmaline, a plausible formula can only be derived for values of M3+/∑M ranging from 0.33 to 0.55 (hence, it must be an oxy-dravite), whereas for the “rim” tourmaline, a plausible formula can only be derived for values of M3+/∑M ranging from 0.00 to 0.18 (hence, it must be a dravite). While this type of calculation is subject to the limitations of analytical error and the challenge of analyzing tourmaline for all components, it is intriguing that the normalization constraints are at least superficially supported by the observed optical property differences (i.e. color in PPL). Nominally, micro-Mössbauer or some other method that can tease out the actual valence states of the Fe (& Mn) in the sample (plus analyses of Li and B and maybe even a structural analysis) are necessary to unequivocally identify these tourmaline species. Still, given the difference in optical properties, however, representative M3+/∑M values of 0.44 (for the “core” composition) and 0.09 (for the “rim” composition) were selected to be close the midpoints of their respective aforementioned successful M3+/∑M ranges, resulting in a different name for each zone. The tourmaline from this sample has been previously analyzed by SIMS (at Arizona State University) for B isotopes: δ11B = -19.3±0.6 ‰. It is not known if the isotopic analysis was done on a core or rim area of the separated crystal.
(unpolarized light)

mineral representative mineral compositions in FKM-102
monazite-(Ce) (Ce0.44La0.19Nd0.17Pr0.05Sm0.03Y0.03Ca0.03Th0.02Gd0.02[HREE]0.01)[P0.98Si0.01O4]
fluorapatite (Ca4.88Mn2+0.05Na0.02FeT0.01Y0.01)[P3.01O12]F1.00
oxy-dravite (“core”; possibly relict) (Na0.68Ca0.02K0.010.29)(Al1.17Mg0.70Fe2+0.57Fe3+0.46Ti0.08Mn2+0.01)(Al5.34Mg0.66)
[Si5.85Al0.15O18](BO3)3(OH)3(O0.70F0.18[OH]0.12)
dravite (“rim”) (Na0.77Ca0.02K0.010.20)(Mg1.29Fe2+1.15Al0.31Fe3+0.12Ti0.10Mn2+0.01)Al6.00
[Si5.83Al0.17O18](BO3)3(OH)3([OH]0.45F0.24O0.31)
muscovite (K0.90Na0.050.05)(Al1.80FeT0.11Mg0.11Ti0.030.95)[Si3.09Al0.91O10]([OH]1.85F0.09O0.06)
annite (K0.930.07)(FeT1.48Mg0.72Al0.40Ti0.14MnT0.040.22)[Si2.73Al1.27O10]([OH]1.49O0.28F0.24)
orthoclase (core; likely relict) (K0.92Na0.04Ba0.01)[Si2.96Al1.04O8]
microcline (overgrowth) (K0.93Na0.04Ba0.01)[Si2.96Al1.04P0.01O8]
albite (Na0.98K0.01)[Si2.97Al1.03O8]

Custer South Dakota tourmaline schist in thin section

same as previous FKM-102 image (under crossed polars).

 




South Africa kimberlite in thin section

sample: FKM-103 (billet from Univ. Arizona petrology collection, sample 191-K-3)
locality: Kimberley, Northern Cape province, South Africa.
rock type: kimberlite.
major mineralogy: largely serpentinized forsterite.
(unpolarized light)

South Africa kimberlite in thin section

same as previous FKM-103 image (under crossed polars).

 




Harding pegmatite New Mexico microlite and lepidolite in thin section

sample: FKM-104
locality: Harding pegmatite, Picuris district, Taos Co., NM, USA.
rock type: mica-rich segregation from Li-Ta pegmatite.
major mineralogy: Orange fluorcalciomicrolite crystals abundantly scattered in a fine-grained pink lithian muscovite, with minor microcline. Rare thin rims of yellow BiVO4 (pucherite?), interstitial to the mica, were verified by EPMA. Interestingly, the specimen was initially labeled as “mimetite in cobaltoan dolomite, from Tsumeb”, and superficially there is a resemblance to that material in hand sample, with lustrous orange/tan crystals in a sugary pink matrix. But note that the crystal morphology of microlite and mimetite are very different(!), and this is further exemplified in thin section by the predictably uniformly isotropic nature of the microlite. Also in thin section, note that mica has a substantially lower birefringence than dolomite. The Li content of the mica is estimated from charge balance and overall analytical total considerations; similarly, a small amount of Rb is assumed in the mica and K-spar from this type of environment, but the Rb contents have not yet been measured. ICP-MS verification of the Li and Rb contents, as well as the determination of other elements potentially present (i.e. B, Cs), is planned.
(unpolarized light)

mineral representative mineral compositions in FKM-104
fluorcalciomicrolite (Ca1.09Na0.86[H2O]0.04?)(Ta1.76Nb0.23W0.01?)O6.00(F0.85[OH]0.09O0.06)
muscovite (K0.82Na0.05Rbx0.13-x)(Al1.99Li0.10MnT0.02FeT0.020.87)[Si2.95Al1.05O10]([OH]1.91F0.09)
microcline (K0.89Na0.05Rbx (x ≤ 0.06))[Si2.97Al1.03O8]

Harding pegmatite New Mexico microlite and lepidolite in thin section

same as previous FKM-104 image (under crossed polars).

 




K2 azurite in thin section

sample: FKM-105 (billet courtesy of C. Loehn, LSU)
locality: “azurite locality”, near K2, Gilgit-Baltistan, Pakistan.
rock type: quartzofeldspathic gneiss. This rock is referred to in the mineral collector & lapidary literature as the “K2 granite”, but the texture is more reminiscent of an orthogneiss.
major mineralogy: This unusual rock contains large (to ~1 cm) nearly spherical bright blue “sunbursts” scattered through the largely quartz+feldspar gneissic matrix (in some hand samples of this material, garnet is also present, but not in the billet from which this thin section was prepared). Muscovite and biotite (~450 ppm Cu), the latter partially altered to chlorite (~1000 ppm Cu), are also present. Although there are indeed small scattered grains of azurite in the “sunbursts”, the bulk of the blue coloration is paler and comes from low z alteration zones in the plagioclase that appear to be a very fine-scale admixture of albite+quartz (calculated at ~70% albite + ~30% quartz at the resolution of the beam, and which contains, in bulk, ~1200 ppm Cu). The nature of this Cu is unclear: whether it is chemically incorporated in the feldspar or quartz, or whether it occurs as sub-micron particles of azurite, chrysocolla or another blue Cu mineral. Overall, the sample shows partial propylitic alteration; in addition to chlorite and the Cu-bearing feldspathic “sunbursts”, there is also minor secondary titanite (~660 ppm Cu) and epidote (not presently analyzed for Cu).
(unpolarized light)

K2 azurite in thin section

same as previous FKM-105 image (under crossed polars).

 




Fen Norway damtjernite in thin section

sample: FKM-106 (billet from Univ. Arizona economic geology collection; sample FEN-5)
locality: Damtjern Lake, Fen complex, Nome, Telemark, Norway.
rock type: “damtjernite”. Lamprophyre associated with the Fen carbonatite.
major mineralogy: test.
(unpolarized light)

Fen Norway damtjernite in thin section

same as previous FKM-106 image (under crossed polars).

 




Madagascar grandidierite in thin section

sample: FKM-107 (billet leftover from FKM M.S. thesis borosilicate calorimetry project; sample 5012)
locality: Mobetsu, Madagascar (note: although this location appears on the mineral dealer label, it has not been located on any examined map of Madagascar).
rock type: test.
major mineralogy: grandidierite.
(unpolarized light)

Madagascar grandidierite in thin section

same as previous FKM-107 image (under crossed polars).

 




Madagascar grandidierite in thin section

sample: FKM-108 (billet leftover from FKM M.S. thesis borosilicate calorimetry project; sample USNM 121887)
locality: Vohibola phlogopite mine, Behara commune, Amboasary district, Tuléar province, Madagascar.
rock type: test.
major mineralogy: grandidierite.
(unpolarized light)

Madagascar grandidierite in thin section

same as previous FKM-108 image (under crossed polars).

 




California garnet glaucophane blueschist in thin section

sample: FKM-109 (billet from Univ. Arizona petrology collection; sample 350:25)
locality: unlabeled, but believed to be from one of the numerous blueschist exposures in Marin or Sonoma Co., CA, USA.
rock type: garnet-lawsonite-glaucophane schist. Blueschist facies (retrogressed eclogite facies) metabasite(?).
major mineralogy: test.
(unpolarized light)

California garnet glaucophane blueschist in thin section

same as previous FKM-109 image (under crossed polars).

 




Crestmore California idocrase skarn in thin section

sample: FKM-110
locality: unlabeled, but believed to be from the Crestmore quarries area, Crestmore, Riverside Co., CA, USA.
rock type: test.
major mineralogy: andradite, vesuvianite, wollastonite.
(unpolarized light)

Crestmore California idocrase skarn in thin section

same as previous FKM-110 image (under crossed polars).

 




glaucophane blueschist in thin section

sample: FKM-111 (billet from Univ. Arizona petrology collection; sample BL-1)
locality: unlabeled (if the sample was donated to the petrology collection by S. Baldwin, it would be from New Caledonia; alternatively, it may be from one of the coastal California blueschist exposures).
rock type: test.
major mineralogy: glaucophane.
(unpolarized light)

glaucophane blueschist in thin section

same as previous FKM-111 image (under crossed polars).

 




Franklin marble clinohumite forsterite spinel marble in thin section

sample: FKM-112 (billet from Univ. Arizona petrology collection)
locality: unlabeled, but believed to be from the Franklin marble, in the general region of Sussex Co., NJ across to Orange Co., NY, USA.
rock type: clinohumite-forsterite-spinel-phlogopite marble. Upper amphibolite to granulite facies meta-dolomite.
major mineralogy: Coarsely crystalline marble with now calcite >> dolomite (dolomite presumably has been significantly consumed to grow spinel and Mg silicates… dolomite is especially abundant within and adjacent to the amphibole, and optically appears slightly “dustier” than the accompanying calcite). Phlogopite, forsterite and spinel are the dominant porphyroblasts. Hydroxyl-clinohumite with patchy zones of more F-dominant clinohumite epitaxially overgrows some of the forsterite (and occasionally phlogopite). Scattered pargasite and apatite are present. Rare small ilmenite, zircon (likely originally detrital) and pyrrhotite are also present. Samples FKM-8, FKM-36 and FKM-184 are additional marbles from the adjoining Sussex Co., NJ/Orange Co., NY area containing humite group minerals. The description under FKM-8 also outlines the rationale for assuming small amounts of boron may be present in the Franklin area humite group minerals (and possibly also in olivine), and provides additional details about features of the normalization scheme.
(unpolarized light)

mineral representative mineral compositions in FKM-112
spinel (Mg0.87Fe2+0.12Zn0.01)Al2.00O4
ilmenite (Fe2+0.55Mg0.42Ti0.02Mn2+0.01)Ti1.00O3
fluorapatite Ca4.99[P2.97Si0.01O12](F0.55[OH]0.40Cl0.05)
forsterite Mg1.00(Mg0.89Fe2+0.10Fe3+0.01)[Si0.99B0.01O4]
hydroxylclinohumite-rich
clinohumite group ss (bulk)
(Mg8.44Fe2+0.40Ti0.11Mn2+0.01)[Si4.04O16]([OH]1.16F0.62O0.22)
clinohumite-rich
clinohumite group ss (patchy)
(Mg8.61Fe2+0.34Ti0.04Mn2+0.01)[Si3.95B0.05O15.95(OH)0.05](F1.18[OH]0.74O0.08)
pargasite (Na0.86K0.14)(Ca1.96Mg0.04)(Mg3.97Al0.68Fe3+0.18Ti0.13V0.02)
[Si6.03Al1.97O22]([OH]1.09F0.61O0.26Cl0.04)
phlogopite (K0.85Na0.100.05)(Mg2.72Al0.17FeT0.07Ti0.030.01)[Si2.86Al1.14O10]([OH]1.42F0.50O0.07Cl0.01)

Franklin marble clinohumite forsterite spinel marble in thin section

same as previous FKM-112 image (under crossed polars).

 




Honolulu Hawaii olivine nephelinite in thin section

sample: FKM-113 (billet from Univ. Arizona petrology collection; sample Hawaii-29)
locality: Training School flow, University of Hawai’i campus, Honolulu, Oahu, Hawai’i, USA.
rock type: olivine nephelinite. Compare to sample FKM-114 (olivine melilitite), also from the Honolulu area.
major mineralogy: specimen acquired for forsterite and nepheline.
(unpolarized light)

Honolulu Hawaii olivine nephelinite in thin section

same as previous FKM-113 image (under crossed polars).

 




Honolulu Hawaii olivine melilitite in thin section

sample: FKM-114 (billet from Univ. Arizona petrology collection; sample Hawaii-30)
locality: Moiliili quarry, Honolulu, Oahu, Hawai’i, USA.
rock type: olivine melilitite. Compare to sample FKM-113 (olivine nephelinite), also from the Honolulu area.
major mineralogy: specimen acquired for forsterite and melilite.
(unpolarized light)

Honolulu Hawaii olivine melilitite in thin section

same as previous FKM-114 image (under crossed polars).

 




Windham Vermont dolomite and chlorite schist in thin section

sample: FKM-115 (this sample is similar to and from the same vicinity as FKM-101)
locality: Windham Co., VT, USA.
rock type: dolomite-chlorite schist. The sample is greenschist facies, with a likely protolith of some type of carbonate-metasomatized mafic (although a bit low in Ca) to ultramafic rock (although a bit high in Al).
major mineralogy: The large pale brown (in hand sample) carbonate rhombs in this schist were reported as ankerite, but have been confirmed by EPMA to be ferroan dolomite. These occur in a fine-grained chlorite matrix along with abundant small porphyroblasts of a Ti-rich hematite. Note the polysynthetic twinning parallel to the short and long axes of the rhomb in the dolomite (best seen in the crossed polar image), which differentiates it and other dolomite-group carbonates from the calcite-group carbonates (twin lamellae in calcite only cross the rhomb parallel to the long axis). Also compare the dolomite in this sample to the typically untwinned magnesite in FKM-133 from an ostensibly identical rock from the Alps.
(unpolarized light)

mineral representative mineral compositions in FKM-115
hematite Fe3+1.00(Fe3+0.65Ti0.17Fe2+0.16V0.01)O3
dolomite (Ca0.99Mn2+0.01)(Mg0.91Fe2+0.09Mn2+0.01)[CO3]2
clinochlore (Mg4.07Al1.02FeT0.71MnT0.01Ni0.010.18)[Si2.93Al1.07O10]([OH]7.99O0.01)

Windham Vermont dolomite talc and chlorite schist in thin section

same as previous FKM-115 image (under crossed polars).

 




Warren county New York garnet sillimanite granulite in thin section

sample: FKM-116 (billet from Univ. Arizona petrology collection; sample 5-4-61-7; this sample is identical to the Wards collection garnet-sillimanite gneiss from the same locality)
locality: Hague township, Warren Co., NY, USA.
rock type: Garnet-sillimanite-[K-spar] gneiss. Middle-upper amphibolite facies metapelitic gneiss (with no co-existing cordierite present, this rock probably should not be considered granulite facies).
major mineralogy: test.
(unpolarized light)

Warren county New York garnet sillimanite granulite in thin section

same as previous FKM-116 image (under crossed polars).

 




Mountain Pass California carbonatite in thin section

sample: FKM-118 (billet courtesy of G. Haxel, U.S.G.S.-Flagstaff)
locality: Mountain Pass mine, San Bernardino Co., CA, USA.
rock type: carbonatite (sovite).
major mineralogy: calcite, barite, quartz, various tiny REE minerals.
(unpolarized light)

Mountain Pass California carbonatite in thin section

same as previous FKM-118 image (under crossed polars).

 




Brumado Brazil uvite talc schist in thin section

sample: FKM-119 (billet from Univ. Arizona petrology collection, courtesy of L. Anovitz)
locality: Brumado, Bahia, Brazil.
rock type: uvite-talc schist. Metamorphosed Mg-metasomatite(?)
major mineralogy: Gemmy greenish to reddish porphyroblasts of uvite in a snow-white fine-grained talc matrix. For the tourmaline, because the total Fe+Mn content is so low, all values of M3+/∑M (M = Fe+Mn) between 0.000 and 1.000 normalize to uvite. Uvite from this sample has been previously analyzed by SIMS (at Arizona State University) for B isotopes: δ11B = +13.4±1.1 ‰.
(unpolarized light)

mineral representative mineral compositions in FKM-119
uvite (OH-dominant) (Ca0.54Na0.270.19)(Mg2.72FeT0.24Ti0.04)(Al5.80Mg0.20)[Si5.85Al0.15O18](BO3)3(OH)3([OH]~0.70F0.20O~0.09)
talc Mg3.00[Si3.97Al0.02O10]([OH]1.96F0.04)

Brumado Brazil uvite talc schist in thin section

same as previous FKM-119 image (under crossed polars).

 




Tien Shan Mountains Tajikistan cancrinite nepheline syenite in thin section

sample: FKM-120 (billet courtesy of J. Worthington, Univ. Arizona; sample 12TS97)
locality: Yasmin Valley, Tien Shan Mtns., Tajikistan.
rock type: nepheline cancrinite syenite.
major mineralogy: test.
(unpolarized light)

Tien Shan Mountains Tajikistan cancrinite nepheline syenite in thin section

same as previous FKM-120 image (under crossed polars).

 




Balmat New York green tremolite schist in thin section

sample: FKM-121
locality: American #1 talc mine, Balmat, St. Lawrence Co., NY, USA.
rock type: tremolite schist. Amphibolite to granulite facies calcareous meta-evaporite, probably with some superimposed metasomatism.
major mineralogy: Almost entirely composed of bright green tremolite (up to 530 ppm Cr; up to 3460 ppm Mn; up to 1640 ppm Fe; compare to the pink tremolite in sample FKM-123), along with minor talc, an interlayer-deficient phlogopite (up to 2510 ppm Cr), calcite, apatite, quartz, zircon, sphalerite and galena. This sample is from the same general vicinity as samples FKM-122 and FKM-123.
(unpolarized light)

mineral representative mineral compositions in FKM-121
fluorapatite (Ca4.93Mn2+0.02Sr0.01Na0.01)[P3.03O12](F0.63[OH]0.24Cl0.14)
tremolite (K0.020.98)(Ca1.87Na0.09Mg0.01)(Mg4.87Al0.05Mn3+0.04Fe3+0.02Cr0.01)[Si8.00O22]([OH]1.84F0.16)
“interlayer deficient phlogopite” (K0.58Na0.02Ca0.010.39)(Mg2.62Al0.11Ti0.06Cr0.02FeT0.010.18)[Si3.49Al0.51O10]([OH]1.72F0.27)
talc (Na0.02Ca0.01)(Mg2.83Al0.02Cr0.01FeT0.010.13)[Si4.00O10]([OH]1.89F0.11)

Balmat New York green tremolite schist in thin section

same as previous FKM-121 image (under crossed polars).

 




Balmat New York donpeacorite and cummingtonite in thin section

sample: FKM-122
locality: ZCA No. 4 mine, Balmat, St. Lawrence Co., NY, USA.
rock type: test.
major mineralogy: Abundant donpeacorite and “manganocummingtonite” (although temporarily renamed “rootname 3” in 2012 by the IMA Subcommittee on Amphibole Classification), with scattered As-rich chlorapatite (molar P:As almost 1:1, so near the chloraptite-turneaureite boundary) and minor Mn-bearing uvite. For the “lower z” tourmaline, mathematically permissible values of M3+/∑M span from 0.467 to 1.000 and normalize to uvite throughout that range. For the “higher z” tourmaline, mathematically permissible values of M3+/∑M span from 0.445 to 0.890 (compositions which normalize to uvite), and from 0.890 to 1.000 (compositions which normalize to a hypothetical “oxy-uvite”). For both tourmaline normalizations presented in the composition table below, the aforementioned lowermost M3+/∑M values of 0.467 and 0.445 were utilized, although these are estimations and have not been independently measured.
(unpolarized light)

mineral representative mineral compositions in FKM-122
chlorapatite (most As-rich) (Ca4.52Mn2+0.33Na0.04Ce0.02La0.01[M+HREE]0.01Sr0.01)
[P1.65As5+1.35S0.02Si0.01O12](Cl0.61[OH]0.27F0.12)
donpeacorite (Mn2+0.54Mg0.44Ca0.02)(Mg0.97Mn3+0.03)[Si1.98Al0.01Fe3+0.01O6]
“manganocummingtonite” (“rootname 3”) (Na0.180.82)(Mn2+1.25Ca0.58Na0.08Mg0.05Fe2+0.05)(Mg4.92Al0.06Fe3+0.02)
[Si7.82Al0.18O22]([OH]1.73F0.25O0.02)
uvite (higher z) (Ca0.53Na0.48Sr0.01)(Mg2.24Fe2+0.41Mn2+0.22Ti0.14)(Al4.68Mg0.81Fe3+0.50)
[Si5.97Al0.03O18](BO3)3(OH)3([OH]0.72F0.28)
uvite (lower z) (Ca0.52Na0.46Sr0.010.01)(Mg2.43Mn2+0.26Fe2+0.20Ti0.11)(Al4.92Mg0.68Fe3+0.40)
[Si5.93Al0.07O18](BO3)3(OH)3([OH]0.71F0.29)

Balmat New York donpeacorite and cummingtonite in thin section

same as previous FKM-122 image (under crossed polars).

 




Gouverneur New York pink tremolite hexagonite in thin section

sample: FKM-123
locality: Gouverneur mine, Fowler, St. Lawrence Co., NY, USA.
rock type: tremolite schist. Amphibolite to granulite facies calcareous meta-evaporite, probably with some superimposed metasomatism..
major mineralogy: Almost entirely composed of pink tremolite (“hexagonite”; only up to 35 ppm Cr; up to 4970 ppm Mn; up to 1660 ppm Fe; compare to the bright green tremolite in sample FKM-121), along with minor talc, calcite, braunite and apatite. This sample is from the same general vicinity as samples FKM-121 and FKM-122.
(unpolarized light)

mineral representative mineral compositions in FKM-123
fluorapatite (Ca4.98Na0.01Sr0.01Y0.01)[P2.98Si0.01O12](F0.50[OH]0.47Cl0.03)
braunite (Mg0.57Mn2+0.24Ca0.04Fe3+0.12Ti0.03)(Mn3+5.74Fe3+0.26)O8[Si0.82Al0.07Fe3+0.11O4]
tremolite (K0.020.98)(Ca1.79Na0.12)(Mg4.85Mn3+0.07Al0.05Fe3+0.02)[Si8.00O22]([OH]1.89F0.11)
talc (Na0.01Ca0.01)(Mg2.89Al0.020.09)[Si4.03O10]([OH]1.97F0.03)

Gouverneur New York pink tremolite hexagonite in thin section

same as previous FKM-123 image (under crossed polars).

 




Burma jadeite in thin section

sample: FKM-124a (billet courtesy of B. Schumer, Univ. Arizona; sampled from the same slab as FKM-124b)
locality: Hpakant-Tawmaw jade tract, Kachin state, Burma.
rock type: blueschist to eclogite facies jadeitite.
major mineralogy: Essentially mono-mineralic jadeite.
(unpolarized light)

Burma jadeite in thin section

same as previous FKM-124a image (under crossed polars).

 




Burma jadeite in thin section

sample: FKM-124b (billet courtesy of B. Schumer, Univ. Arizona; sampled from the same slab as FKM-124a)
locality: Hpakant-Tawmaw jade tract, Kachin state, Burma
rock type: blueschist to eclogite facies jadeitite.
major mineralogy: Essentially mono-mineralic jadeite.
(unpolarized light)

Burma jadeite in thin section

same as previous FKM-124b image (under crossed polars).

 




Willsboro New York garnet diopside and wollastonite marble in thin section

sample: FKM-126
locality: Lewis mine, Willsboro, Essex Co., NY, USA.
rock type: grossular-diopside-wollastonite marble. Pyroxene hornfels facies metacarbonate.
major mineralogy: test.
(unpolarized light)

Willsboro New York garnet diopside and wollastonite marble in thin section

same as previous FKM-126 image (under crossed polars).

 




Bahia Brazil sodalite in thin section

sample: FKM-127
locality: Hiassu farm, Itaju do Colônia, Bahia, Brazil.
rock type: carbonatite-associated sodalite syenite.
major mineralogy: test.
(unpolarized light)

Bahia Brazil sodalite in thin section

same as previous FKM-127 image (under crossed polars).

 




Ruoutevare Sweden hogbomite and hercynite in thin section

sample: FKM-128 (billet courtesy of G. Färber, Gunnar Färber Minerals)
locality: Ruoutevare, 13 km N of Kvikkjokk, Lappland, Sweden.
rock type: test.
major mineralogy: Reported to contain magnesiohögbomite-2N2S, but no högbomite-family minerals are present in this thin section.
(unpolarized light)

Ruoutevare Sweden hogbomite and hercynite in thin section

same as previous FKM-128 image (under crossed polars).

 




Vermont R33 zircon quartz monzodiorite in thin section

sample: FKM-129 (billet courtesy of J. Aleinikoff, U.S.G.S.-Denver; host rock of the R33 zircon geochronology standard [419±1 Ma])
locality: Braintree complex, VT, USA.
rock type: deuteric-altered quartz-monzodiorite.
major mineralogy: test.
(unpolarized light)

Vermont R33 zircon quartz monzodiorite in thin section

same as previous FKM-129 image (under crossed polars).

 




Alaska eudialyte in thin section

sample: FKM-130 (billet courtesy of D. Bradley, U.S.G.S.-Anchorage)
locality: “eudialyte prospect”, Windy Fork granite pluton, McGrath distict, Alaska Range, AK, USA.
rock type: test.
major mineralogy: eudialyte.
(unpolarized light)

Alaska eudialyte in thin section

same as previous FKM-130 image (under crossed polars).

 




Mary Kathleen Australia andradite allanite and stillwellite skarn in thin section

sample: FKM-131 (self-collected in July 1996)
locality: Mary Kathleen mine, near Mary Kathleen townsite (abandoned), northwest QLD, Australia.
rock type: “skarn”-like calc-silicate metasomatite.
major mineralogy: Predominately massive andradite garnet, with abundant allanite-(Ce) and sparse stillwellite-(Ce).
(unpolarized light)

Mary Kathleen Australia andradite allanite and stillwellite skarn in thin section

same as previous FKM-131 image (under crossed polars).

 




Johnsburg New York serendibite and sinhalite in thin section

sample: FKM-132
locality: Armstrong Farm, near Johnsburg township, Warren Co., NY, USA.
rock type: test.
major mineralogy: serendibite, sinhalite.
(unpolarized light)

Johnsburg New York serendibite and sinhalite in thin section

same as previous FKM-132 image (under crossed polars).

 




Zillertal Austria magnesite talc and serpentine schist in thin section

sample: FKM-133
locality: Zillertal, Austria.
rock type: magnesite-talc-“serpentine” schist. The sample is greenschist facies, with a likely protolith of some type of carbonate-metasomatized ultramafic rock (although a bit high in Al).
major mineralogy: Inspection of the hand sample shows what appears to be porphyroblasts of a brownish rhombohedral carbonate in a chlorite schist matrix. The carbonate is ferroan magnesite (= “breunnerite”). Note the lack of polysynthetic twinning in the magnesite (in the crossed polar image), which differentiates it from calcite and also the dolomite-group carbonates (compare this sample to the very similar appearing FKM-115, which however contains dolomite rather than magnesite). In thin section, the dominant sheet silicate has gray birefringence, although at a very fine-scale, areas of higher birefringence are also visible. Coarser blades of talc (and with “invisible” talc likely contributing to the higher birefringence of some of the fine-grained material) are also visible. Under BSE imaging, the coarse talc can be subtly differentiated the from finer-grained dominant sheet silicate, which appears homogeneous. However, analyses of the dominant sheet silicate do not normalize well to either an 8[OH] sheet silicate (chlorite and serpentine-kaolinite groups) or to a 2[OH] sheet silicate (mica and talc-pyrophyllite groups), and in fact appear to be intermediate between the two (and chlorite, talc and mica analyses from other samples done with the same calibration normalized as expected). Based on the analyses of this sample, the sheet silicate could be effectively normalized to a mixed layer composition of approximately 2:1 ratio of talc to an aluminous serpentine (and is presented in the composition table as such). Interlayering in sheet silicates is probably more common than appreciated, and may be suspected macroscopically when carefully done analyses yield unusual stoichiometries (see for example Veblen, 1983 [and references therein]). It is certainly possible that true interlayering is not present, but rather that the mono-mineralic domains are simply at a finer scale than discernible with microprobe beam resolution; this question could be resolved with TEM imaging. Abundant small porphyroblasts of ilmenite are present, as well as scattered tiny zoned rutile, apatite and monazite. Trace elements in the zoned rutile include ~93 ppm Zr, ~186 ppm Sn and ~243 ppm Cr in the low-z portion, and ~276 ppm Zr, ~155 ppm Sn and ~356 ppm Cr in the high-z portion.
(unpolarized light)

Zillertal Austria magnesite talc and serpentine schist in thin section

same as previous FKM-133 image (under crossed polars).

 




Johnsburg New York serendibite in thin section

sample: FKM-134
locality: unlabeled, but believed to be from Armstrong Farm, near Johnsburg township, Warren Co., NY, USA.
rock type: test.
major mineralogy: serendibite.
(unpolarized light)

Johnsburg New York serendibite in thin section

same as previous FKM-134 image (under crossed polars).

 




serendibite in thin section

sample: FKM-135
locality: unlabeled, but believed to be from one of the NY or Madagascar serendibite/grandidierite occurrences.
rock type: test.
major mineralogy: serendibite.
(unpolarized light)

serendibite in thin section

same as previous FKM-135 image (under crossed polars).

 




Monte Somma Italy meionite in thin section

sample: FKM-136
locality: San Vito quarry, San Vito, Ercolano, Monte Somma, Somma-Vesuvius complex, Naples province, Campania, Italy.
rock type: metasomatized(?) sanidinite facies meta-calcareous ejectum.
major mineralogy: Scattered meionite crystals along the N and E edges of the the thin section (these were growing into open vugs), in a largely carbonate matrix.
(unpolarized light)

Monte Somma Italy meionite in thin section

same as previous FKM-136 image (under crossed polars).

 




Stillwater complex Montana bronzite orthopyroxenite in thin section

sample: FKM-137 (billet from Univ. Arizona petrology collection)
locality: unlabeled, but believed to be from the Stillwater complex, MT, USA.
rock type: orthopyroxenite (“bronzitite”).
major mineralogy: Essentially only orthopyroxene.
(unpolarized light)

Stillwater complex Montana bronzite orthopyroxenite in thin section

same as previous FKM-137 image (under crossed polars).

 




Spurr mine Michigan chloritoid in thin section

sample: FKM-138
locality: Spurr mine, Imperial Heights, Baraga Co., MI, USA.
rock type: test.
major mineralogy: chloritoid.
(unpolarized light)

Spurr mine Michigan chloritoid in thin section

same as previous FKM-138 image (under crossed polars).

 




Colorado riebeckite alkali granite in thin section

sample: FKM-139 (billet from Univ. Arizona petrology collection)
locality: unlabeled, but believed to be from El Paso Co., CO, USA.
rock type: alkali granite pegmatite.
major mineralogy: Quartz, microcline perthite, riebeckite, aegirine.
(unpolarized light)

Colorado riebeckite alkali granite in thin section

same as previous FKM-139 image (under crossed polars).

 




Fuka mine Japan tilleyite marble in thin section

sample: FKM-140
locality: Fuka mine, Fuka, Bicchi-cho, Takahashi City, Okayama prefecture, Japan.
rock type: tilleyite-bearing marble. Sanidinite facies metacarbonate.
major mineralogy: test.
(unpolarized light)

Fuka mine Japan tilleyite marble in thin section

same as previous FKM-140 image (under crossed polars).

 




Laytonville California howieite riebeckite and stilpnomelane blueschist in thin section

sample: FKM-141
locality: Laytonville quarry, Laytonville, Mendocino, Co., CA, USA.
rock type: test.
major mineralogy: specimen acquired for howieite, riebeckite and stilpnomelane.
(unpolarized light)

Laytonville California howieite riebeckite and stilpnomelane blueschist in thin section

same as previous FKM-141 image (under crossed polars).

 




Galgenberg Austria chloritoid schist in thin section

sample: FKM-142
locality: Galgenberg, near Leoben, Steirmark, Austria.
rock type: test.
major mineralogy: specimen acquired for chloritoid.
(unpolarized light)

Galgenberg Austria chloritoid schist in thin section

same as previous FKM-142 image (under crossed polars).

 




Iron Cap mine Arizona johannsenite in thin section

sample: FKM-143
locality: Iron Cap mine, Graham Co., AZ, USA.
rock type: test.
major mineralogy: specimen acquired for johannsenite.
(unpolarized light)

Iron Cap mine Arizona johannsenite in thin section

same as previous FKM-143 image (under crossed polars).

 




Halsjoberg Sweden wyllieite and scorzalite advanced argillic alteration assemblage in thin section

sample: FKM-144
locality: Hålsjöberg, Torsby, Värmland, Sweden.
rock type: test.
major mineralogy: specimen acquired for wyllieite and scorzalite.
(unpolarized light)

Halsjoberg Sweden wyllieite and scorzalite advanced argillic alteration assemblage in thin section

same as previous FKM-144 image (under crossed polars).

 




Norra Karr Sweden catapleiite and eudialyte in thin section

sample: FKM-145
locality: Norra Kärr, Gränna, Jönköping, Småland, Sweden.
rock type: test.
major mineralogy: specimen acquired for eudialyte and catapleiite.
(unpolarized light)

Norra Karr Sweden catapleiite and eudialyte in thin section

same as previous FKM-145 image (under crossed polars).

 




Norra Karr Sweden rosenbuschite in thin section

sample: FKM-146
locality: Norra Kärr, Gränna, Jönköping, Småland, Sweden.
rock type: test.
major mineralogy: specimen acquired for rosenbuschite.
(unpolarized light)

Norra Karr Sweden rosenbuschite in thin section

same as previous FKM-146 image (under crossed polars).

 




Laytonville California zussmanite and deerite blueschist in thin section

sample: FKM-147
locality: Laytonville quarry, Laytonville, Mendocino, Co., CA, USA.
rock type: deerite-stilpnomelane-zussmanite metaquartzite. Blueschist facies ferruginous metaquartzite.
major mineralogy: Quartz and zussmanite are the dominant minerals in this sample, with subordinate deerite and a K-deficient stilpnomelane. Minor apatite, chalcopyrite and pyrrhotite are also present, as well as a sparse poikioblastic allanite zoned from a La-rich ferriallanite core to a Nd-rich allanite. This material was challenging to analyze due to prolific fine quartz inclusions, and the measured Si concentrations from both the core and rim analyses were corrected for a small amount (less than 2%) of quartz contamination (to force normalized Si = 3.00). The relative enrichments in La and Nd relative to Ce in these allanites are likely a function of locally high redox conditions and a resulting higher-than-typical Ce4+/∑Ce ratio (and so less Ce3+ available for allanite). This sample is from the same locality as samples FKM-15 and FKM-141, also from blueschist facies ferruginous metaquartzite, but of somewhat differing protolith bulk compositions and hence differing alkali-Fe-silicate mineralogy. Normalization of stilpnomelane and zussmanite are complex owing to possible vacancies in the A and M sites, variable Fe3+ and/or Mn3+ in the M site, and potentially variable hydroxyl (in both minerals) and excess water (in stilpnomelane). For this sample, the stilpnomelane is normalized to three assumptions: (a) 20 T+M cations (permits no vacancies in the M site), (b) 6[OH] per 36 total [O+OH] (this conforms to a sheet silicate T4O10 skeleton and also yields a reasonable M3+/∑M [M = Fe+Mn] ≈ 0.37), and finally (c) 5 moles of excess H2O (which brings the overall total to almost exactly 100 wt%). The normalization is similar to that of the stilpnomelane in FKM-15. The zussmanite was similarly normalized to (a) 30 to 31 A+M cations (permits up to one vacancy in the M site, and allows flexibility in estimating a reasonable M3+/∑M [M = Fe+Mn]… in this case, ~0.17)) and (b) 14[OH] per 56 total [O+OH] to provide a constraint on the charge balance.
(unpolarized light)

mineral representative mineral compositions in FKM-147
fluorapatite (Ca4.90Fe2+0.03Mn2+0.02Sr0.01Na0.01)[P3.02O12](F0.58[OH]0.42)
ferriallanite-(La) ss
(core)
(Ca0.72Mn2+0.18Fe2+0.10Na0.01)(La0.25Nd0.24Ce0.20Ca0.14Pr0.07Sm0.04[HREE]0.03Gd0.02Y0.01Th0.01)
(Fe3+0.56Al0.29V0.13Ti0.03)Al1.00(Fe2+0.89Fe3+0.10Mg0.01)O[Si2.00O7][Si1.00O4](OH)
allanite-(Nd) ss
(rim)
(Ca0.73Mn2+0.16Fe2+0.10Na0.01)(Nd0.27La0.25Ce0.21Ca0.09Pr0.07Sm0.04[HREE]0.03Gd0.02Sr0.02Th0.01)
(Al0.56Fe3+0.36V0.07Ti0.01)Al1.00(Fe2+0.90Fe3+0.09Mg0.01)O[Si2.00O7][Si1.00O4](OH)
deerite (Fe2+4.77Mn2+0.46Fe3+0.19V0.13Ti0.10Mg0.06Cr0.010.28)(Fe3+2.96Al0.04)O3[Si6.00O17](OH)5
zussmanite
(most Mn-rich)
(K0.76Na0.100.14)(FeT10.16MnT1.12Mg0.87V0.03Zn0.010.81)[Si16.90Al1.02O42](OH)14
zussmanite
(most Al-rich)
(K0.88Na0.04Ba0.010.07)(FeT10.54Mg0.96MnT0.66Al0.01V0.010.82)[Si16.45Al1.55O42](OH)14
“K-deficient stilpnomelane” (K0.02Ca0.02Na0.010.95)(FeT5.96MnT1.15Mg0.50Al0.31Ni0.05V0.03)[Si10.96Al1.03O~30](OH)~6 . ~5H2O

Laytonville California zussmanite and deerite blueschist in thin section

same as previous FKM-147 image (under crossed polars).

 




Gascoyne Junction Western Australia kimberlite in thin section

sample: FKM-148
locality: near Gascoyne Junction (Brockman Creek?), WA, Australia.
rock type: reported to be a kimberlite, but this sample actually is an olivine nephelinite (i.e., compare this sample with another example of nephelinite FKM-113, and also with a classic kimberlite FKM-103). The sample appears to be somewhat agglomeratic.
major mineralogy: Phenocrysts of large strongly-zoned forsterite in a matrix of intergrown very fine nepheline and somewhat coarser, slightly-zoned clinopyroxene (sometimes as crystal sprays). From multiple analytical spots, the nepheline did not give a good analyses, due in part to the very fine grain size, possible admixture with other material, and likely alkali migration caused by the electron beam. A zoned Cr-rich (core) to Fe-Ti-rich (rim) spinel is also prevalent, as is scattered apatite and rare Ni-(Cu)-sulfide. Minor chlorite alteration is locally present.
(unpolarized light)

mineral representative mineral compositions in FKM-148
chromite-rich spinel ss (core) (Fe2+0.67Mg0.31Mn2+0.01)(Cr1.51Al0.24Fe3+0.17Ti0.04Fe2+0.04)O4
magnetite-rich spinel ss (rim; most Ti-rich) (Fe2+0.86Mg0.10Mn2+0.03Ca0.01)(Fe3+0.64Fe2+0.54Ti0.52Al0.25Si0.04)O4
fluorapatite (Ca4.88Sr0.03Ce0.03Fe0.03La0.01Nd0.01)[P2.87Si0.13O12](F0.68[OH]0.27Cl0.04)
forsterite (core; most Mg-rich) Mg0.99(Mg0.80Fe2+0.19Ni0.01)[Si1.00O4]
forsterite (rim; most Fe-rich) (Mg0.95Mn2+0.03Ca0.02)(Fe2+0.86Mg0.14)[Si1.00O4]
diopside (core) (Ca0.93Mg0.05Na0.02)(Mg0.81Fe2+0.10Fe3+0.05Ti0.02)[Si1.90Al0.09O6]
diopside (rim) (Ca0.92Mg0.04Na0.04)(Mg0.62Fe2+0.14Fe3+0.11Ti0.08Al0.04)[Si1.71Al0.29O6]
clinochlore (K0.02Ca0.01)(Mg3.00FeT1.24Al1.01MnT0.030.02)[Si3.85Al0.15O10]([OH]7.94F0.06)
nepheline (needs re-analysis) (Na0.73K0.09Ca0.01)[Si1.18Al0.81O4]

Gascoyne Junction Western Australia kimberlite in thin section

same as previous FKM-148 image (under crossed polars).

 




Sarany Russia uvarovite and magnesiochromite in thin section

sample: FKM-149
locality: Saranovskii mine, Saranovskaya village, Permskaya Oblast’ (middle Ural Mtns. region), Russia.
rock type: hydrothermally altered and metamorphosed chromitite.
major mineralogy: Sector zoned birefringent uvarovite with minor intergrown calcite, filling veins in a massive granular chromite-magnesiochromite ss. Minor alteration chromian clinochlore is also present.
(unpolarized light)

mineral representative mineral compositions in FKM-149
chromite-rich spinel ss (Fe2+0.76Mg0.23Mn2+0.01)(Cr1.61Al0.30Fe3+0.04Fe2+0.02V0.01Ti0.01Si0.01)O4
magnesiochromite-rich spinel ss (Mg0.61Fe2+0.38Mn2+0.01)(Cr1.13Al0.70Fe3+0.15Fe2+0.01Ti0.01)O4
uvarovite (most Cr-rich) (Ca2.97Fe2+0.02Mg0.01)(Cr1.29Al0.61Ti0.09V0.01)[Si2.91Al0.09O11.99F0.01]
uvarovite (most Al-rich) Ca3.00(Cr1.04Al0.89Fe3+0.03Ti0.03V0.01)[Si2.96Al0.03O12]
clinochlore (Mg3.99Al0.90Cr0.78FeT0.07Ni0.020.24)[Si2.75Al1.25O10](OH)8.00

Sarany Russia uvarovite and magnesiochromite in thin section

same as previous FKM-149 image (under crossed polars).

 




Norway cyprine thulite in thin section

sample: FKM-151
locality: Øvstebø, Kleppan, Sauland, Hjartdal, Telemark, Norway.
rock type: test.
major mineralogy: specimen acquire for Cu-bearing vesuvianite (“cyprine”).
(unpolarized light)

Norway cyprine thulite in thin section

same as previous FKM-151 image (under crossed polars).

 




Durham Ranch Wyoming ferro-indialite paralava in thin section

sample: FKM-152
locality: Durham Ranch, near Wright, Campbell Co., WY, USA.
rock type: paralava.
major mineralogy: Ferro-indialite (the high-T hexagonal dimorph of sekaninaite) reported, but not observed in this thin section. In fact, no recognizable minerals were observed in the dark essentially glassy matrix of this sample.
(unpolarized light)

Durham Ranch Wyoming ferro-indialite paralava in thin section

same as previous FKM-152 image (under crossed polars).

 




Nusfjord Lofoten Norway sadanagaite in thin section

sample: FKM-153
locality: Nusfjord, Flakstadøya, Lofoten, Nordland, Norway.
rock type: test.
major mineralogy: reported as potassic-chloro-ferro-sadanagaite, but no amphibole present in this thin section.
(unpolarized light)

Nusfjord Lofoten Norway sadanagaite in thin section

same as previous FKM-153 image (under crossed polars).

 




Barberton South Africa stichtite and chrysotile asbestos in thin section

sample: FKM-154
locality: New Amianthus mine, Kaapsche, Barberton, Mpumalanga province, South Africa.
rock type: pervasively altered chromitite or similar chromite-rich ultramafic rock.
major mineralogy: Massive stichtite (of undetermined polytype) veined with chrysotile, with sparse scattered tiny chromite.
(unpolarized light)

Barberton South Africa stichtite and chrysotile asbestos in thin section

same as previous FKM-154 image (under crossed polars).

 




Afghanistan marialite scapolite and gypsum meta-evaporite in thin section

sample: FKM-155
locality: “evaporite occurrence”, Sar-e-Sang, Koksha valley, Badakhshan province, Afghanistan.
rock type: Scapolite-bearing gypsum rock. Retrogressed high-grade(?) meta-evaporite.
major mineralogy: Porphyroblasts of purple (in hand sample) marialite in a groundmass of fine-grained gypsum (anhydrite at peak metamorphic conditions?) Sample FKM-25, also from Sar-e-Sang, may represent a carbonate-dominated facies depositionally-related to the evaporite facies represented by this sample.
(unpolarized light)

Afghanistan marialite scapolite and gypsum meta-evaporite in thin section

same as previous FKM-155 image (under crossed polars).

 




Russia chrysoberyl schist in thin section

sample: FKM-156
locality: Malyshevo mine, near Ekaterinburg, Sverdlovskaya Oblast’ (middle Ural Mtns. region), Russia.
rock type: chrysoberyl-chlorite-biotite schist. This schist likely has a significant metasomatic component.
major mineralogy: Chrysoberyl porphyroblasts in a matrix of clinochlore and fluorian phlogopite. In BSE imaging, the chrysoberyl shows irregular higher “z” patches that appear to be mildly-enriched in Sn (up to 0.76 wt% Sn). It is uncertain if this Sn is actually in solid solution, or is present as dispersed sub-micron “invisible” cassiterite. For comparison, another chrysoberyl-bearing sample featured here is FKM-16.
(unpolarized light)

mineral representative mineral compositions in FKM-156
chrysoberyl (higher “z” zones) (Al1.94FeT0.05Sn0.01)[Be1.00O4]
chrysoberyl (main “z”) (Al1.95FeT0.05)[Be0.99Al0.01O4]
phlogopite (K0.75Na0.090.16)(Mg2.57FeT0.23Al0.20)[Si2.92Al1.08O10]([OH]1.57F0.43)
clinochlore (Mg4.23Al1.23FeT0.44MnT0.010.09)[Si2.89Al1.11O10]([OH]7.86F0.14)

Russia chrysoberyl schist in thin section

same as previous FKM-156 image (under crossed polars).

 




Lovozero Kola Russia mangan-neptunite and aegirine syenite in thin section

sample: FKM-157
locality: Lovozero massif, Kola Peninsula, Murmanskaja Oblast’, Russia.
rock type: test.
major mineralogy: specimen acquired for mangan-neptunite.
(unpolarized light)

Lovozero Kola Russia mangan-neptunite and aegirine syenite in thin section

same as previous FKM-157 image (under crossed polars).

 




Khit Ostrov Karelia Russia corundum ruby gneiss in thin section

sample: FKM-158
locality: Khit Ostrov, Karelia Republic, Russia.
rock type: corundum-garnet amphibolite. This sample shows some similarity to sample FKM-24, but that rock lacks garnet and its plagioclase is essentially end-member anorthite. This rock seems to have a lower bulk Mg/(Mg+Fe) ratio than FKM-24.
major mineralogy: Rock is predominately calcic amphibole and plagioclase (oligoclase). Porphyroblasts of large corundum (pink in hand sample) and smaller almandine garnet (only weakly zoned) are abundant. Scattered phlogopite is present, containing patchy chlorite. Along some of the amphibole-phlogopite contacts, the amphibole has been superficially altered to chlorite, and in one instance the secondary chlorite was further rimmed by a thin band of nearly end-member albite (this being in contact with a slightly higher-z zone of the adjacent mica). In both the corundum and the garnet, sparse small allanite-(Ce) grains, partially but significantly altered to REE-carbonates(?) are observed. Ilmenite (in part altering to rutile) and rutile by itself (perhaps after ilmenite?) make up the oxide phases. The rutile also contains ~1660 ppm Cr and ~963 ppm Zr as additional trace elements.
(unpolarized light)

mineral representative mineral compositions in FKM-158
corundum Al2.00O3
ilmenite (Fe2+0.94Mg0.05)Ti1.01O3
rutile (Ti0.99Fe3+0.01)O2
almandine (core) (Fe2+1.68Mg1.02Ca0.29Mn2+0.02)(Al1.93Fe3+0.06)[Si3.00O12]
almandine (rim) (Fe2+1.81Mg0.89Ca0.27Mn2+0.02)(Al1.94Fe3+0.06)[Si2.99Al0.01O12]
allanite-(Ce) (altered) (Ca0.97Na0.03)(Ca0.43Ce0.28La0.13Nd0.08Pr0.03Th0.02Sm0.01Sr0.01)Al0.97Al1.00
(Al0.47Fe2+0.41Mg0.08Ti0.01)(O0.82Cl0.11F0.08)[Si1.92Al0.08O7][Si0.96Al0.04O4](OH)
tschermakite (Na0.39K0.040.57)(Ca1.51Na0.39Fe2+0.09Mn2+0.01)(Mg2.31Al1.18Fe3+0.96Fe2+0.40Ti0.12V0.01Cr0.01Ni0.01)[Si5.77Al2.22O22]([OH]1.74O0.24F0.02)
phlogopite (main) (K0.78Na0.030.19)(Mg1.79FeT0.61Al0.45Ti0.10Cr0.01Ni0.010.03)[Si2.69Al1.31O10]([OH]1.79O0.19F0.02)
phlogopite (rim along secondary albite) (K0.68Na0.19Ba0.010.12)(Mg1.77FeT0.65Al0.44Ti0.09Cr0.01Ni0.010.03)
[Si2.62Al1.38O10]([OH]1.81O0.17F0.02)
“partially chloritized mica” (K0.23Ca0.04Na0.01)(Mg3.00Al1.34FeT0.99Ti0.13V0.01Cr0.01Ni0.010.51)
[Si3.04Al0.96O10]([OH]~6.1O0.26F0.02)
clinochlore (rimming amphibole) (Ca0.03Na0.01)(Mg2.76FeT1.58Al1.22MnT0.01V0.01Cr0.01Ni0.010.40)[Si3.05Al0.95O10]([OH]7.99O0.0.01)
“oligoclase” (Na0.72Ca0.28)[Si2.68Al1.32O8]

Khit Ostrov Karelia Russia corundum ruby gneiss in thin section

same as previous FKM-158 image (under crossed polars).

 




Orford Nickel mine Canada diopside and grossular in thin section

sample: FKM-159
locality: Orford Nickel mine, St. Denis de Brompton, Estrie, Québec, Canada.
rock type: test.
major mineralogy: specimen acquired for diopside and grossular.
(unpolarized light)

Orford Nickel mine Canada diopside and grossular in thin section

same as previous FKM-159 image (under crossed polars).

 




Mont Saint-Hilaire Canada sodalite nepheline syenite in thin section

sample: FKM-160
locality: Mont Saint-Hilaire, Montérégie, Québec, Canada.
rock type: sodalite-nepheline syenite.
major mineralogy: test.
(unpolarized light)

Mont Saint-Hilaire Canada sodalite nepheline syenite in thin section

same as previous FKM-160 image (under crossed polars).

 




Picuris district New Mexico actinolite epidote and garnet in thin section

sample: FKM-161
locality: Picuris district, Taos Co., NM, USA.
rock type: test.
major mineralogy: specimen acquired for actinolite.
(unpolarized light)

Picuris district New Mexico actinolite epidote and garnet in thin section

same as previous FKM-161 image (under crossed polars).

 




Kilbourne Hole New Mexico mantle peridotite xenolith in thin section

sample: FKM-162
locality: Kilbourne Hole, Doña Ana Co., NM, USA.
rock type: spinel peridotite xenolith in basalt.
major mineralogy: The basalt-hosted xenolith is predominately made up of coarse forsterite and chrome diopside, with subordinate enstatite and dark green spinel.
(unpolarized light)

mineral representative mineral compositions in FKM-162
spinel (Mg0.78Fe2+0.21Ni0.01)(Al1.80Cr0.18Fe3+0.01)O4
forsterite Mg0.99(Mg0.78Fe2+0.21Ni0.01)[Si1.01O4]
enstatite (Mg0.96Ca0.03Na0.01)(Mg0.69Fe2+0.19Al0.10Cr0.01)[Si1.89Al0.11O6]
diopside (core) (Ca0.74Na0.13Mg0.12)(Mg0.68Al0.19Fe2+0.06Fe3+0.03Cr0.02Ti0.01)[Si1.86Al0.14O6]
diopside (rim) (Ca0.85Mg0.11Na0.04)(Mg0.77Al0.10Fe2+0.07Cr0.02Ti0.02Fe3+0.01)[Si1.86Al0.13O6]

Kilbourne Hole New Mexico mantle peridotite xenolith in thin section

same as previous FKM-162 image (under crossed polars).

 




Graves Mountain Georgia lazulite advanced argillic alteration assemblage in thin section

sample: FKM-163
locality: Graves Mtn., Lincoln Co., GA, USA.
rock type: argillaceous meta-quartzite. Metamorphosed quartz-sericite to argillic alteration assemblage.
major mineralogy: Lazulite, kyanite, muscovite, and an opaque (probably hematite), in a matrix of quartz of two distinct sizes. The larger quartz grains could possibly represent relict quartz eyes, suggesting that prior to metamorphism, and prior to the preceding advanced argillic alteration, the original rock may have been a quartz phenocryst porphyry.
(unpolarized light)

Graves Mountain Georgia lazulite advanced argillic alteration assemblage in thin section

same as previous FKM-163 image (under crossed polars).

 




Altay pegmatite China holmquistite in thin section

sample: FKM-164
locality: Altay pegmatite, Fuyun Co., Xianjiang Autonomous Region, China.
rock type: metasomatized wallrock adjacent to Li pegmatite.
major mineralogy: specimen acquired for holmquistite.
(unpolarized light)

Altay pegmatite China holmquistite in thin section

same as previous FKM-164 image (under crossed polars).

 




Yates mine Otter Lake Canada titanite diopside allanite and scapolite marble in thin section

sample: FKM-165
locality: Yates mine, Otter Lake, Outaouais, Québec, Canada.
rock type: allanite-titanite-scapolite-diopside carbonate rock. The descriptive but non-interpretational term “carbonate rock” is used here because there is debate as to whether rocks of this nature, in this region of the Grenville Province, are primarily metamorphic + metasomatic (and so would be classified as “marbles” or perhaps “skarns”), or whether they may have formed from melt fluxed by metasomatic fluids (and so might better considered as “crustal carbonatite”, or perhaps “carbonatitic migmatite”). The carbonate rocks occur in what are known as “vein-dikes”, again suggesting ambiguity between a metasomatic and a migmatitic origin.
major mineralogy: Salmon orange (in hand sample) calcite with abundant diopside, titanite, and scapolite intermediate between marialite and meionite. Scattered allanite is present, both as discrete crystals and as irregular rims between other minerals (e.g. between calcite and titanite, or between calcite and scapolite), and scattered apatite is also present. Minor quartz, zircon, and epidote (seemingly secondary) are present. The titanite contains ~916 ppm Zr.
(unpolarized light)

mineral representative mineral compositions in FKM-165
fluorapatite (Ca4.99Sr0.01Y0.01)[P2.97Si0.01S0.01O12](F0.69[OH]0.31)
titanite (Ca0.99Ce0.01)(Ti0.76Al0.19Fe3+0.03Nb0.01)(O0.77F0.19[OH]0.04)[Si0.99Al0.01O4]
allanite-(Ce) Ca0.99(Ca0.35Ce0.35La0.15Nd0.09Pr0.03Sm0.01[M+HREE]0.01Sr0.01)(Al0.87Fe3+0.12Ti0.02)Al1.00
(Fe2+0.51Fe3+0.37Mg0.12)O[Si1.98Al0.02O7][Si1.00O4](OH)
epidote (alteration?) Ca1.00(Ca0.93Sr0.06)Al1.00Al1.00(Fe3+0.83Al0.16Mg0.01)(O0.99F0.01Cl0.01)[Si1.99Al0.01O7][Si1.00O4](OH)
diopside (Ca0.94Na0.05Mn2+0.01)(Mg0.66Fe2+0.26Fe3+0.04Al0.02)[Si1.98Al0.02O6]
phlogopite (K0.91Ba0.010.08)(Mg2.30FeT0.56Al0.05Ti0.02MnT0.010.06)[Si3.03Al0.97O10](F1.05[OH]0.89O0.04Cl0.02)
scapolite (“wernerite”) (Na1.48Ca1.32K0.17Sr0.03)[Si7.63Al4.36Fe3+0.01O24] . (Ca0.52Na0.42)([CO3]0.42Cl0.36[SO4]0.13)

Yates mine Otter Lake Canada titanite diopside allanite and scapolite marble in thin section

same as previous FKM-165 image (under crossed polars).

 




Bahia Brazil chrome tourmaline and fuchsite schist in thin section

sample: FKM-166
locality: Serra de Jacobina gold district, Bahia, Brazil.
rock type: tourmaline-fuchsite schist. Likely a metamorphosed sericite-dominant alteration assemblage, accompanying mesothermal “Mother Lode”-type Au mineralization.
major mineralogy: Predominately coarse bright green Cr-bearing muscovite (fuchsite), interlayered with abundant bands of Cr-rich oxy-dravite and quartz. Scattered chromite is also present. Reported M3+/∑M (M = Fe+Mn) and O/(O+OH) in the tourmaline analyses are estimations and have not been independently measured (although total Fe+Mn is low). For the low-Cr oxy-dravite only, values of M3+/∑M < 0.175 normalize to dravite instead of oxy-dravite.
(unpolarized light)

mineral representative mineral compositions in FKM-166
chromite
(poor stoichiometry;
re-analysis warranted)
(Fe2+0.73Mg0.06Mn2+0.04Zn0.02)(Cr1.37Al0.76V0.01)O4
oxy-dravite (most Cr-rich) (Na0.66Ca0.13K0.01Sr0.010.19)(Mg1.85Cr0.94Fe2+0.10Fe3+0.05Ti0.04V0.01)(Al5.88Fe3+0.12)
[Si5.88Al0.12O18](BO3)3(OH)3(O0.90F0.08[OH]0.02)
oxy-dravite (least Cr-rich) (Na0.56Ca0.23K0.010.20)(Mg2.14Cr0.57Fe2+0.12Fe3+0.12Ti0.03V0.01)(Al5.93Fe3+0.07)
[Si5.85Al0.15O18](BO3)3(OH)3(O0.64[OH]0.22F0.14)
muscovite (K0.82Na0.040.14)(Al1.68Cr0.15Mg0.13Ti0.08FeT0.04V0.010.91)[Si3.09Al0.91O10]([OH]1.79O0.16F0.05)

Bahia Brazil chrome tourmaline and fuchsite schist in thin section

same as previous FKM-166 image (under crossed polars).

 




Graves Mountain Georgia pyrophyllite and kyanite advanced argillic alteration assemblage in thin section

sample: FKM-167
locality: Graves Mtn., Lincoln Co., GA, USA.
rock type: kyanite-pyrophyllite schist. Metamorphosed advanced argillic alteration assemblage.
major mineralogy: Largely pyrophyllite with abundant scattered kyanite. Widespread, fine-grained, undifferentiated Fe-oxide; minor rutile and quartz; very small amounts of a U(+) mineral of moderate relief and 1st order white birefringence… likely an alunite-group mineral, such as alunite, crandallite, or woodhouseite.
(unpolarized light)

Graves Mountain Georgia pyrophyllite and kyanite advanced argillic alteration assemblage in thin section

same as previous FKM-167 image (under crossed polars).

 




Picuris Range New Mexico zoisite thulite in thin section

sample: FKM-168
locality: Picuris Range, Glenwoody district, Taos Co., NM, USA.
rock type: calc-silicate “skarn”.
major mineralogy: Zoisite (thulite?), vesuvianite, quartz, some garnet, and abundant As-rich apatite (up to 7.8 wt% [0.55 apfu] As).
(unpolarized light)

Picuris Range New Mexico zoisite thulite in thin section

same as previous FKM-168 image (under crossed polars).

 




Poona India cavansite and stilbite in thin section

sample: FKM-170
locality: Wagholi quarries, Wagholi, Pune district, Maharashtra, India.
rock type: cavities in zeolite facies metasomatized basalt.
major mineralogy: Cavansite and stilbite, with minor calcite.
(unpolarized light)

Poona India cavansite and stilbite in thin section

same as previous FKM-170 image (under crossed polars).

 




St. Marcel Italy alurgite in thin section

sample: FKM-171 (billet courtesy of P. Lecumberri-Sanchez, Univ. Arizona)
locality: Prabornaz mine, Saint-Marcel, Val d’Acosta, Italy.
rock type: muscovite-biotite-braunite schist. Greenschist to amphibolite facies meta-Mn-rich sediment (distal volcanogenic exhalite?), with superimposed metasomatism.
major mineralogy: Braunite appears to be the dominant mineral, with additional abundant muscovite (“alurgite”) and biotite (either “manganophyllite” or possibly even shirozulite) admixed with quartz and feldspar. Minor piemontite or Mn-rich epidote is present. Sample FKM-2 is also from the Prabornaz mine, but represents a different assemblage.
(unpolarized light)

St. Marcel Italy alurgite in thin section

same as previous FKM-171 image (under crossed polars).

 




El Hoyazo Spain lower crustal felsic granulite in thin section

sample: FKM-172 (billet courtesy of B. Jenkins, Freeport-McMoRan Copper & Gold Inc., Oro Valley office)
locality: El Hoyazo, Níjar, Almería, Andalusia, Spain.
rock type: lower crustal felsic granulite xenolith in calc-alkaline potassic magma.
major mineralogy: garnet, biotite, sillimanite (“fibrolite”).
(unpolarized light)

El Hoyazo Spain lower crustal felsic granulite in thin section

same as previous FKM-172 image (under crossed polars).

 




South Africa sugilite in thin section

sample: FKM-173
locality: N’Chwaning III mine, Kuruman, Kalahari manganese field, Northern Cape Province, South Africa.
rock type: quartz-pectolite-sugilite metasomatite. This rocks was originally a bedded Mn-rich sediment, that was subsequently metasomatized and metamorphosed.
major mineralogy: The sample is composed of an abundant, somewhat globular and vuggy MAl-dominant end-member of sugilite (this may be a new mineral), overgrown by similarly botryoidal sugilite sensu strictu (where Fe3+ dominates the M site). Within the sugilite are very tiny irregular grains of aegirine (relict?), whereas within the “Al-rich sugilite” are larger scattered patches of an amphibole gradational in composition between a relatively Li-enriched potassic richterite and a slightly Li-enriched sodic amphibole close to “potassic-magnesio-mangani-arfvedsonite” (which may also be a new species). Surrounding and interspersed with the sugilite masses are irregular discontinuous veinlets of quartz + pectolite (zoned in CL from pale centers to bright yellow rims). Also scattered throughout the rock but especially abundant along a coarse band rimmed by sugilite are small irregular clusters of several Ba-Sr-Mn silicates. These clusters are predominately Ba-bearing hennomartinite, with tiny overgrowths of Sr-bearing cherchiaraite-(Mn), and patches of a new ruizite-like mineral with both Ca sites occupied by Sr (cf. taniajacoite). Note that the reported Li contents for the sugilite, amphiboles and pectolite are estimates based on stoichiometry and charge balance constraints and have not been verified by instrumental means.
(unpolarized light)

mineral representative mineral compositions in FKM-173
hennomartinite (Sr0.90Ba0.11)(Mn3+1.99Fe3+0.01)[Si1.98O7](OH)2.00 . H2O
“SrSr-ruizite” Sr1.00(Sr0.82Ca0.18Na0.01)Mn3+1.99[Si3.99O11(OH)2]([OH]1.99F0.01) . 2H2O
cherchiaraite-(Mn) (Ba3.76Sr0.06Na0.03K0.01Ca0.010.13)(Mn3+3.69Fe3+0.010.30)
[Si4.14O12]O2(OH)4[Si2.07O3(OH)4]([OH]1.32Cl0.68)
sugilite (rim) (K0.990.01)(Na1.990.01)(Fe3+1.11Mn3+0.72Al0.07Mn2+0.06Ti0.02Mg0.01)
(Li2.98Si0.03)[Si12.00O30]
“Al-sugilite” (core) (K0.990.01)(Na1.930.07)(Al1.10Mn3+0.57Fe3+0.27Mn2+0.04Mg0.02Ti0.01)
(Li2.93Al0.07)[Si11.99Al0.01O30]
aegirine (Na0.96Ca0.03Mg0.01)(Fe3+0.88Mn3+0.05Mg0.04Al0.02Ti0.01)[Si2.00O6]
pectolite (Na0.93Li0.06Sr0.01)(Ca1.91Mn2+0.07Na0.02)[Si3.00O8(OH)]
potassic-richterite-rich amphibole ss (K0.65Na0.23Sr0.11)(Na1.36Ca0.59Li0.05)(Mg4.35Li0.26Mn3+0.25Fe3+0.13)
[Si8.00O22]([OH]1.98F0.02)
≈”potassic-magnesio-mangani-
arfvedsonite”-rich amphibole ss
(K0.73Na0.14Sr0.13)(Na1.54Ca0.31Li0.14)(Mg4.38Mn3+0.33Fe3+0.15Li0.14)
[Si8.00O22](OH)2.00

South Africa sugilite in thin section

same as previous FKM-173 image (under crossed polars).

 




Načetín Czech Republic fayalite in thin section

sample: FKM-174
locality: Načetín, Poběžovice, Plzeň region, Bohemia, Czech Republic.
rock type: Unclear, but this sample could possibly be a “ferro-dunite” that has undergone some metasomatism. Examples of “ferro-dunite” (but with olivine significantly more magnesian, and with magnetite as the dominant oxide) occur as mantle xenoliths in northern Bohemia (e.g. Ulrych et al., 2000).
major mineralogy: The rock is composed almost entirely of sub-parallel crystals of slightly enlongated olivine (Fa65Fo35). Patches and zones of amphibole (secondary?) are scattered around the olivine, and in some cases form clear alteration rims. This amphibole is essentially a ferri-tschermakite, although in places it approaches magnesio-hastingsite in composition. This amphibole itself shows zones of further alteration to tremolite, clinochlore and veinlets of an Al-bearing greenalite. Ilmenite forms large scattered masses, as well as veinlets penetrating the amphibole and olivine. Fine to less commonly more coarse exsolution of magnetite are associated with the ilmenite. Along one edge of the sample is a thick vein of greenalite that differs somewhat from the greenalite veinlets in the amphibole. The entire sample is highly fractured, primarily in two nearly-perpendicular directions that both parallel and cross-cut olivine crystals.
(unpolarized light)

mineral representative mineral compositions in FKM-174
ilmenite (Fe2+0.95Mg0.03Mn2+0.02Fe3+0.01)Ti1.00O3
magnetite (Fe2+0.98Mg0.01Mn2+0.01)(Fe3+1.61Fe2+0.12Ti0.12V0.08Al0.05Cr0.01)O4
fayalite (Mg0.69Fe2+0.28Mn2+0.02)(Fe2+0.99Fe3+0.01)[Si0.99Fe3+0.01O4]
ferri-tschermakite-rich amphibole ss
(bulk)
(Na0.30K0.040.66)(Ca1.53Na0.47)(Mg2.56Fe3+1.75Fe2+0.33Al0.27Ti0.04Mn2+0.03V0.01)
[Si6.09Al1.91O22]([OH]1.91O0.08F0.01)
ferri-tschermakite-rich amphibole ss
(approaching magnesio-hastingsite)
(Na0.40K0.080.52)(Ca1.70Na0.30)(Mg2.70Fe3+1.27Fe2+0.64Ti0.15Al0.14V0.05Mn2+0.02Sc0.01
Cr0.01)[Si6.33Al1.67O22]([OH]1.70O0.30)
tremolite (Na0.14Ca0.07K0.010.78)(Ca1.65Fe2+0.33Mn2+0.02)(Mg3.70Fe2+1.26V0.02Sc0.01Ti0.01)
[Si7.69Al0.31O22]([OH]1.98O0.02)
clinochlore (Mg3.48FeT1.25Al1.05MnT0.010.21)[Si2.95Al1.05O10]([OH]7.99O0.01)
greenalite (veinlets in amphibole) Ca0.01(FeT3.04Mg2.34Al0.26MnT0.050.31)[Si3.95Al0.05O10]([OH]7.97Cl0.02O0.01)
greenalite (veins in olivine) Ca0.01(FeT2.67Mg2.36MnT0.05Al0.010.91)[Si4.00O10](OH)8.00

Načetín Czech Republic fayalite in thin section

same as previous FKM-174 image (under crossed polars).

 




Norra Kärr Sweden fluoro-leakeite in thin section

sample: FKM-175
locality: Norra Kärr, Gränna, Jönköping, Småland, Sweden.
rock type: add rock type.
major mineralogy: specimen acquired for eckermannite (however, the occurrence of eckermannite at Norra Kärr is disputed, and the amphibole previously identified as eckermannite is now believed to be fluoro-leakeite).
(unpolarized light)

Norra Kärr Sweden fluoro-leakeite in thin section

same as previous FKM-175 image (under crossed polars).

 




Vysoký Kámen Czech Republic koechilinite and powellite in thin section

sample: FKM-176
locality: feldspar quarry, Vysoký Kámen, Krásno, Horní Slavkov, Czech Republic.
rock type: add rock type.
major mineralogy: specimen acquired for koechilinite and powellite.
(unpolarized light)

Vysoký Kámen Czech Republic koechilinite and powellite in thin section

same as previous FKM-176 image (under crossed polars).

 




Rana Norway høgtuvaite in thin section

sample: FKM-177
locality: Høgtuva beryllium deposit, Rana, Nordland, Norway.
rock type: add rock type.
major mineralogy: specimen acquired for høgtuvaite.
(unpolarized light)

Rana Norway høgtuvaite in thin section

same as previous FKM-177 image (under crossed polars).

 




Bjurliden Sweden gahnite in thin section

sample: FKM-178
locality: Bjurliden, Norsjö, Västerbotten, Sweden.
rock type: add rock type.
major mineralogy: specimen acquired for gahnite. For comparison, another gahnite-bearing sample featured here (in quartz rather than admixed with sulfides) is FKM-12. Additionally, several of the Franklin, NJ samples show a somewhat atypical orange to yellow gahnite (e.g. FKM-45 and FKM-48).
(unpolarized light)

Bjurliden Sweden gahnite in thin section

same as previous FKM-178 image (under crossed polars).

 




Crestmore California monticellite and hydroxylapatite in thin section

sample: FKM-179
locality: Crestmore quarries, Crestmore, Riverside Co., CA, USA.
rock type: high-grade monticellite marble. Contact aureole (high-T low-P; sanidinite(?) facies) metamorphosed siliceous carbonate, with additional metasomatic contribution from the causative intrusion.
major mineralogy: Sample is predominately calcite (pale blue in hand sample) with abundant mm-sized porphyroblasts of monticellite and a P-bearing hydroxylellestadite (incorrectly identified on the dealer label as hydroxylapatite; P-rich ellestadite from Crestmore was formerly known as “wilkeite” and was originally thought to be a distinct species). Small scattered garnet crystals occur both as inclusions in monticellite and as discrete grains in the calcite; some are variably and irregularly zoned, whereas others are nearly homogeneous. Cr, Sc, Zr and Y are variably-enriched in the garnet. Minor gypsum is present (likely secondary… occurs along a weathered surface), and sparse tiny chalcocite is scattered within the calcite. For comparison, an essentially identical monticellite-bearing sample featured here, also from Crestmore, is FKM-10.
(unpolarized light)

mineral representative mineral compositions in FKM-179
hydroxylellestadite (Ca4.98Na0.01)[Si1.20S1.15P0.63V0.01O12]([OH]0.72F0.16Cl0.12)
monticellite Ca1.00(Mg0.90Fe2+0.08)[Si1.01O4]
grossular-rich garnet ss (most Al+Zr-rich) (Ca2.98Mg0.02)(Al0.94Fe3+0.70Cr0.18Ti0.08Sc0.03Zr0.03Mg0.03)[Si2.90Al0.10O12]
andradite-rich garnet ss (most Cr+Sc-rich) (Ca2.90Mg0.06Y0.02)(Fe3+0.74Al0.68Cr0.46Sc0.06Ti0.05Zr0.01)[Si2.90Al0.10O12]
andradite-rich garnet ss (most Fe-rich) Ca3.00(Fe3+1.94Fe2+0.02Mg0.01)[Si3.02O12]

Crestmore California monticellite and hydroxylapatite in thin section

same as previous FKM-179 image (under crossed polars).

 




Ilímaussaq Greenland narsarsukite in thin section

sample: FKM-180
locality: Kangerdluarsuk Fjord, Ilímaussaq complex, Narsaq, Kujalleq, Greenland.
rock type: add rock type.
major mineralogy: specimen acquired for narsarsukite.
(unpolarized light)

Ilímaussaq Greenland narsarsukite in thin section

same as previous FKM-180 image (under crossed polars).

 




Ilímaussaq Greenland naujakasite in thin section

sample: FKM-181
locality: Kangerdluarsuk Fjord, Ilímaussaq complex, Narsaq, Kujalleq, Greenland.
rock type: add rock type.
major mineralogy: specimen acquired for naujakasite.
(unpolarized light)

Ilímaussaq Greenland naujakasite in thin section

same as previous FKM-181 image (under crossed polars).

 




Ludvika Sweden knebelite and hematite in thin section

sample: FKM-182
locality: Stolberg, by Ludvika, Dalarna, Sweden.
rock type: high grade tephroite-hematite-rhodochrosite metasomatite. Some might call this sample a “skarn”, but I prefer to use that term specifically for a calc-silicate rock derived from metasomatism by an adjacent de-volatilizing crystallizing magma. In contrast, this rock isn’t quite “calc”, per se (with Mn > Ca), and also it may likely be a metamorphosed and metasomatized Mn-Fe exhalite with perhaps only an indirect relationship to magmatism (for example, as a heat source to drive hydrothermal fluid circulation).
major mineralogy: The rock is composed of roughly equal parts carbonate, oxide, and silicate. Small quantities of sulfides (pyrrhotite, chalcopyrite, galena and sphalerite) and fluorapatite are also present. The oxide is hematite with a small Mn component. The carbonate occurs as three distinct phases: a coarsely crystalline high-Ca rhodochrosite (which appears as the nearly colorless material in the unpolarized light scanned image) and an intimate mixture of kutnohorite and high-(Mg+Fe) rhodochrosite (these latter two carbonates are finer-grained and slightly more grayish-colored in the unpolarized light scanned image). The abundant “shattered” material in the images is “knebelite” (= a mixed Mg+Fe-rich Mn-dominant olivine [tephroite]). This material is similar to that in FKM-48 but is Fe2+ > Mg and is also Zn-free. As discussed in greater detail with respect to the tephroite in FKM-48, in this case as well the Mn2+ content is only roughly 1 apfu, so it is possible there is significant ordering of Mn2+ into the slightly larger M2 site and Mg+Fe into the slightly smaller M1 site. If this is the case, the “knebelite” in this sample, as with the material in FKM-48, may be a new ordered olivine rather than tephroite sensu strictu. The light brown material in the scanned image is a hydrous Mn-Mg-Fe silicate of varying Mn and Mg content and is a bit challenging to identify due to its fine-grained nature. Based on the optical properties of slightly coarser zones and the Si=4 normalizations, the material is most likely an Mn-rich member of the serpentine family (=caryopilite). Other less likely possibilities include a member of the chlorite family (=gonyerite) or pyrosmalite-(Mn). All three species are prevalent in many of the central Sweden Mn deposits. (unpolarized light)

mineral representative mineral compositions in FKM-182
pyrrhotite Fe0.88S1.00
chalcopyrite Cu1.00Fe1.00S2.00
hematite (Fe3+1.94Mn3+0.04Al0.02)O3
rhodochrosite (most Mg+Fe-rich) (Mn2+0.49Mg0.24Fe2+0.20Ca0.07)[CO3]
rhodochrosite (most Ca-rich) (Mn2+0.45Ca0.28Mg0.19Fe2+0.08)[CO3]
kutnohorite (Ca0.84Mn2+0.16)(Mn2+0.56Mg0.34Fe2+0.10)[CO3]2
fluorapatite (Ca4.90Mn2+0.07Fe2+0.02)[P3.00O12](F0.86[OH]0.11Cl0.03)
“MnFe2+[SiO4]” olivine
(most Mn-rich; historically tephroite)
Mn2+1.00(Fe2+0.66Mn2+0.25Mg0.08Fe3+0.01)[Si0.99Fe3+0.01O4]
“MnFe2+[SiO4]” olivine
(most Mg-rich; historically tephroite)
(Mn2+0.92Mg0.08)(Fe2+0.72Mg0.27Fe3+0.01)[Si0.99Fe3+0.01O4]
caryopilite? (Mn2+2.28Mg1.50Fe2+~0.94Fe3+~0.85Al0.010.43)
[Si4.00O10]([OH]7.97Cl0.03)
“Mg-caryopilite”? Ca0.01(Mg1.87Mn2+1.63Fe3+~1.49Fe2+~0.14Al0.070.79)
[Si4.00O10]([OH]7.97F0.02Cl0.01)

Ludvika Sweden knebelite and hematite in thin section

same as previous FKM-182 image (under crossed polars).

 




Fuka mine Japan hillebrandtite and spurrite in thin section

sample: FKM-183
locality: Fuka mine, Fuka, Bicchi-cho, Takahashi City, Okayama prefecture, Japan.
rock type: add rock type.
major mineralogy: specimen acquired for hillebrandtite and spurrite.
(unpolarized light)

Fuka mine Japan hillebrandtite and spurrite in thin section

same as previous FKM-183 image (under crossed polars).

 




Edenville New York warwickite marble in thin section

sample: FKM-184
locality: Edenville, near Warwick, Orange Co., NY, USA.
rock type: warwickite-forsterite-spinel-clinohumite marble. Granulite facies meta-siliceous dolostone (the boron and fluorine may be of metasomatic origin?)
major mineralogy: The sample is a magnesian marble, but with calcite > dolomite (likely due in part to the combination of dolomite-consuming + calcite-forming reactions to produce metamorphic Mg minerals). These Mg minerals include scattered spinel and relict forsterite “cores”, the latter largely replaced by clinohumite. The normalizations of both the forsterite and clinohumite suggest slight Si deficiencies in their “T” sites; small amounts of boron (~0.28 wt% B) were added to both minerals to improve their site occupancies and analytical totals. See the discussion under sample FKM-8 for more detail about the normalization scheme used for the humite group minerals, and the rationale for estimating possible boron in humite group minerals and olivine from B-rich Franklin marble assemblages. Warwickite (with 1400 ppm Zr) is the boron phase present in this sample. The warwickite shows incipient alteration along fractures to numerous tiny ilmenite grains (too small to give a good analysis), although larger discrete masses of ilmenite are also present. Sparse zirconolite is associated with the larger ilmenite; zirconolite occurrences in marble are not widely reported, so this occurrence is notable. Some special zirconolite composition and normalization features to note: HREE were estimated by an approximate linear extrapolation of the chondrite-normalized REE plot of measured L+MREE. Mg in zirconolite was presently overlooked and has been estimated here to improve the site occupancies and overall analytical total; the actual concentration of Mg, as well as the concentrations of a few additional potentially key elements (e.g. Sc) will be verified at the next opportunity and then updated here. The zirconolite normalization is based on 4 cations. However, charge balancing to the conventional 7[O] anion content did not yield satisfactory results. This suggests that the zirconolite may be partially hydrated due to radiation damage (for example, Blatt et al., 1987 propose that non-measured water accounts for their low analytical totals in high-actinide zones of zirconolite from Malawi). To account for this possibility, the zirconolite normalization allowed up to 1[O] to be replaced with 1[OH] (hence akin to a pyrochlore composition), with concomitant flexibility in assigning an M3+/∑M ratio (M = Fe+Mn) between 0 and 1. A value of M3+/∑M = 0.5 was assumed here, yielding the estimated [OH] content shown in the composition table below. Although this approach allows an estimate of the valences of Fe and Mn, Fe and Mn were reported as FeT and MnT, respectively, to emphasize the high uncertainty in this calculation in light of the present need to estimate some element concentrations. Rounding out the thin section mineralogy is a mass of talc on one side of the sample (presumably after a pre-existing Mg silicate), and veinlets of clinochlore cutting the clinohumite/forsterite crystals. Samples FKM-8, FKM-36 and FKM-112 are also examples of Franklin marble exposures from the adjoining Orange Co., NY/Sussex Co., NJ area containing humite group minerals. Sample FKM-37, also from the Franklin marble, is another B-bearing sample [with fluoborite].
(unpolarized light)

mineral representative mineral compositions in FKM-184
spinel (Mg0.83Fe2+0.16Zn0.01)Al1.99O4
ilmenite (Fe2+0.73Mg0.21Mn2+0.04Ti0.01Ca0.01)Ti1.00O3
zirconolite (Ca0.46Y0.14U0.14[HREE]~0.13Th0.07Nd0.03Gd0.02Ce0.01Sm0.01)(Zr0.82Ti0.17Hf~0.01)
(Ti1.24FeT0.44Mg~0.27MnT0.02Nb0.01)(O~6.52[OH]~0.48)
calcite (Ca0.97Mg0.03)[CO3]
dolomite Ca1.00(Mg0.97Fe2+0.44)[CO3]2
warwickite (Mg1.24Ti0.33Al0.19Fe2+0.13Fe3+0.10V0.01)(O0.96F0.04)[BO3]
forsterite Mg1.00(Mg0.85Fe2+0.13Fe3+0.01)[Si0.96B0.04O3.98F0.02]
clinohumite (Mg8.43Fe2+0.45Ti0.10Mn2+0.02Fe3+0.01)[Si3.82B0.18O15.82(OH)0.18](F1.10[OH]0.70O0.20)
talc (Mg2.73FeT0.220.05)[Si3.99Al0.01O10]([OH]1.86F0.13)
clinochlore (Mg4.56Al1.14FeT0.18V0.010.11)[Si2.90Al1.09O10]([OH]7.88F0.11)

Edenville New York warwickite marble in thin section

same as previous FKM-184 image (under crossed polars).

 




Falotta Switzerland tinzenite in thin section

sample: FKM-185
locality: Falotta, Tinzen, Switzerland.
rock type: add rock type.
major mineralogy: specimen acquired for tinzenite.
(unpolarized light)

Falotta Switzerland tinzenite in thin section

same as previous FKM-185 image (under crossed polars).

 




Kuntá Hora Czech Republic anthophyllite in thin section

sample: FKM-186
locality: Malšov, by Kuntá Hora, Czech Republic.
rock type: add rock type.
major mineralogy: specimen acquired for anthophyllite.
(unpolarized light)

Kuntá Hora Czech Republic anthophyllite in thin section

same as previous FKM-186 image (under crossed polars).

 




Dehesa California dumortierite in thin section

sample: FKM-187
locality: Dehesa, San Diego Co., CA, USA.
rock type: add rock type. Compare this sample to the similar boron-bearing advanced argillic alteration assemblage in sample FKM-61 and FKM-70.
major mineralogy: specimen acquired for dumortierite.
(unpolarized light)

Dehesa California dumortierite in thin section

same as previous FKM-187 image (under crossed polars).

 




Norberg Sweden dollaseite in thin section

sample: FKM-188
locality: Norberg area, Västmanland, Sweden.
rock type: add rock type.
major mineralogy: Sample is largely composed of dollaseite-(Ce) and tremolite, with subordinate calcite and scattered gadolinite-(Nd) [Nd here is slightly greater than Ce, which is the next most abundant REE. This may be a new species; however, the full REE distribution should be verified by SIMS or ICP-MS]. In one area of the thin section, patchy talc is intergrown with the calcite, and rare small fluorite is also present (also associated with the calcite). Rare tiny magnetite inclusions in the dollaseite-(Ce) are also observed.
(unpolarized light)

mineral representative mineral compositions in FKM-188
magnetite Fe2+1.00Fe3+2.00O4
gadolinite-(Nd) (Nd0.60Ce0.55Y0.26Sm0.17Gd0.12La0.12Pr0.10[HREE]0.06Ca0.02)
(Fe2+0.69Mg0.13Ga0.010.17)(Be1.94Si0.06)[Si1.00O4]2(O1.74[OH]0.22F0.03)
dollaseite-(Ce) (Ca0.93Y0.03[HREE]0.01Gd0.01)(Ce0.54La0.30Nd0.14Pr0.05Sm0.01)(Mg0.81Fe3+0.17)
(Al0.97Fe3+0.03)(Mg0.88Fe2+0.10Mn2+0.02)(F0.71O0.28)[Si2.00O7][Si1.01O4](OH)
tremolite (Na0.01K0.010.98)(Ca1.96Na0.04)(Mg4.73Fe2+0.20Al0.05Mn2+0.01)[Si7.98Al0.02O22]([OH]1.32F0.68)
talc (Ca0.04Na0.01)(Mg2.73FeT0.10Al0.010.16)[Si4.03O10]([OH]1.88F0.12)

Norberg Sweden dollaseite in thin section

same as previous FKM-188 image (under crossed polars).

 




Isle of Mull Scotland mullite and corundum in thin section

Isle of Mull Scotland mullite and corundum in thin section

sample: FKM-189 (two thin sections cut from the same billet are shown here)
locality: Loch Scridain area, Isle of Mull, Scotland, UK.
rock type: add rock type.
major mineralogy: specimen acquired for mullite and corundum.
(unpolarized light)

Isle of Mull Scotland mullite and corundum in thin section

Isle of Mull Scotland mullite and corundum in thin section

same as previous FKM-189 image pair (under crossed polars).

 




Nippyo mine Japan proto-ferro-suenoite in thin section

sample: FKM-190
locality: Nippyo mine, Awano, Kanuma City, Tochigi Prefecture, Honshu Island, Japan.
rock type: add rock type.
major mineralogy: specimen acquired for proto-ferro-mangano-anthophyllite (which has since been renamed as proto-ferro-suenoite), pyroxmangite and pyrophanite.
(unpolarized light)

Nippyo mine Japan proto-ferro-suenoite in thin section

same as previous FKM-190 image (under crossed polars).

 




Madagascar hibonite in thin section

sample: FKM-191
locality: Andrakaholo, Anosy region, Tuléar province, Malagasy Republic.
rock type: spinel-hibonite-corundum-anorthite granulite. The protolith was likely an argillaceous carbonate.
major mineralogy: The sample is composed primarily of near end-member anorthite. Porphyroblasts of corundum are abundant (and are loaded with several types of fluid ± solid inclusions), along with scattered large porphyroblasts of spinel and hibonite. The hibonite is patchy zoned in REE. Minor calcite and baddeleyite, rare phlogopite, and a single thorianite crystal are also present. Within one baddeleyite is also a single small crystal of zirconolite. This sample bears some similarity to FKM-205 and comes from the same vicinity in Madagascar.
(unpolarized light)

mineral representative mineral compositions in FKM-191
spinel (Mg0.87Fe2+0.13)Al2.00O4
corundum Al2.00O3
hibonite (most REE-rich) (Ca0.64Ce0.18La0.12Sr0.02Nd0.01Pr0.01Th0.01)(Al10.94Mg0.61Ti0.29Fe2+0.08Fe3+0.04Si0.04)O19
hibonite (most Ti-rich) (Ca0.97Sr0.02Na0.01Ce0.01Nd0.01Th0.01)(Al10.59Ti0.62Mg0.57Fe2+0.12Si0.05Fe3+0.02)O19
zirconolite (Ca0.67Y0.09U0.09Th0.06[HREE]0.04Gd0.01Sm0.01Nd0.01Ce0.01)
Zr1.00(Ti1.41Al0.19Zr0.17Fe2+0.15Nb0.04Hf0.01V0.01)O7
fluorapatite (Ca4.97Y0.01Ce0.01Nd0.01)[P2.93Si0.04O12](F0.98[OH]0.01Cl0.01)
phlogopite (K0.89Na0.06Ba0.020.03)(Mg2.74Al0.17FeT0.05Ti0.03)[Si2.81Al1.19O10]([OH]1.10F0.84O0.07)
anorthite (Ca0.98Na0.01)[Al2.02Si1.98O8]

Madagascar hibonite in thin section

same as previous FKM-191 image (under crossed polars).

 




Arkansas wollastonite in thin section

sample: FKM-192
locality: Union Carbide Mine, Wilson Springs (Potash Sulfur Springs), Garland Co., Arkansas, USA.
rock type: add rock type.
major mineralogy: specimen acquired for wollastonite (and aegirine seems present as well).
(unpolarized light)

Arkansas wollastonite in thin section

same as previous FKM-192 image (under crossed polars).

 




Långban Sweden cymrite in thin section

sample: FKM-193
locality: Långban, Filipstad, Värmland, Sweden.
rock type: add rock type.
major mineralogy: specimen acquired for cymrite. This sample is mineralogically very similar to FKM-86, also from Långban, and also contains melanotekite and phlogopite.
(unpolarized light)

Långban Sweden cymrite in thin section

same as previous FKM-193 image (under crossed polars).

 




Abtenau Austria crossite in thin section

sample: FKM-194
locality: Webing, near Abtenau, Salzburg, Austria.
rock type: add rock type.
major mineralogy: specimen acquired for crossite.
(unpolarized light)

Abtenau Austria crossite in thin section

same as previous FKM-194 image (under crossed polars).

 




Sunnyside mine Colorado pyroxmangite in thin section

sample: FKM-195
locality: Sunnyside mine, Silverton, CO, USA.
rock type: add rock type.
major mineralogy: specimen acquired for pyroxmangite.
(unpolarized light)

Sunnyside mine Colorado pyroxmangite in thin section

same as previous FKM-195 image (under crossed polars).

 




Namibia cassiterite tin granite in thin section

sample: FKM-196
locality: unspecified locality in Namibia.
rock type: cassiterite-bearing granite.
major mineralogy: specimen acquired for cassiterite.
(unpolarized light)

Namibia cassiterite tin granite in thin section

same as previous FKM-196 image (under crossed polars).

 




Tasmania stichtite and serpentine in thin section

sample: FKM-197
locality: southwestern Tasmania, Australia, possibly from the BHP prospect, Birches Inlet, Macquarie Harbour locality.
rock type: add rock type.
major mineralogy: specimen acquired for stichtite and serpentine.
(unpolarized light)

Tasmania stichtite and serpentine in thin section

same as previous FKM-197 image (under crossed polars).

 




Greenwood Maine tourmaline and lepidolite in thin section

sample: FKM-198
locality: Black Mountain, Greenwood, Oxford Co., Maine, USA.
rock type: add rock type.
major mineralogy: specimen acquired for elbaite and lepidolite.
(unpolarized light)

Greenwood Maine tourmaline and lepidolite in thin section

same as previous FKM-198 image (under crossed polars).

 




Namibia shattuckite in thin section

sample: FKM-199
locality: Kaokoveld Plateau, Kunene region, Namibia.
rock type: add rock type.
major mineralogy: specimen acquired for shattuckite.
(unpolarized light)

Namibia shattuckite in thin section

same as previous FKM-199 image (under crossed polars).

 




Red Cloud mine New Mexico bastnasite and fluorite in thin section

sample: FKM-200
locality: Red Cloud Fluorite mine, Gallinas Mts, Red Cloud District, Lincoln Co., New Mexico, USA.
rock type: add rock type.
major mineralogy: specimen acquired for bastnasite-(Ce) and fluorite.
(unpolarized light)

Red Cloud mine New Mexico bastnasite and fluorite in thin section

same as previous FKM-200 image (under crossed polars).

 


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