samples FKM-201 to FKM-300

 

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Switzerland calderite in thin section

sample: FKM-201
locality: Schmorrasgrat-Süd, Starlera, Ferrera Valley, Grischun, Switzerland.
rock type: add rock type.
major mineralogy: Calderite was reported for this sample, but all of the garnet examined in this thin section was verified by EPMA as Mn-rich andradite (however, with a significant calderite component). In addition to garnet, aggregates of Mn-enriched aegirine-augite admixed with a calcite-rhodochrosite solid-solution carbonate are present. Several large patchy-zoned barite crystals are also present, and thin irregular discontinuous veinlets of hematite are abundant in the garnet.
(unpolarized light)

mineral representative mineral compositions in FKM-201
hematite (Fe3+1.99Mn3+0.01)O3
calcite (Ca0.63Mn2+0.35Mg0.02)[CO3]
barite (most Sr-rich) (Ba0.94Sr0.04Na0.01)[S1.00O4]
barite (main) (Ba0.97Sr0.02Na0.01)[S1.00O4]
andradite (Ca1.83Mn2+1.16Mg0.01)(Fe3+1.82Al0.12Mn3+0.05)[Si2.99O12]
aegirine-augite (Na0.75Ca0.23Mn2+0.02)(Fe3+0.71Mn2+0.15Mg0.10Al0.02Mn3+0.01)[Si2.00O6]

Switzerland calderite in thin section

same as previous FKM-201 image (under crossed polars).

 




Argentina hibonite and grossite in thin section

sample: FKM-202
locality: “hibonite locality”, Sierra de Comechingones, San Luis province, Argentina.
rock type: This rock is purportedly from a natural occurrence, but it bears a strong resemblance to an artificial smelter by-product, and is questioned as such in the mindat locality description. However, the overall sample texture, the lack of silicates that would normally be expected to be encountered in conventional vanadium-refining slag, and the somewhat atypical low-Fe composition of the vanadium present in the sample all suggest that if this actually is a smelter product, it’s not necessarily an ordinary commercial one (i.e. one that is the by-product of the routine production of ferro-vanadium). Alternatively, it is perhaps possible that this sample represents a lab-grown material (e.g. the by-product of a thermite reaction to produce vanadium), as such an origin would allow for much more flexibility with regard to both texture (i.e. control of the cooling rate) and the bulk composition. As for the possibility that this is from a natural occurrence, I wouldn’t want to rule that out based only on this one sample. However, I remain extremely skeptical. Although high-grade metamorphism is described from the area from which this sample is reported (but almost certainly not as “ultra”-UHT as this material would seem to require… droplets of what was once molten vanadium are present!), I’m hard-pressed to imagine a natural protolith with this bulk composition that can also end up so strongly reduced. Given the unusual and perhaps even unique nature of this material if it is indeed natural, I would definitely like to see the original collectors publish a detailed geologic description of the occurrence in the peer-reviewed literature.
major mineralogy: This sample is enigmatic and bears no petrologic similarity to the well-known hibonite-bearing rocks of Madagascar (for example, see sample FKM-191); indeed, this sample bears little resemblance to any typical terrestrial rock. Unlike the silicate- and carbonate-rich bulk mineralogy of the Madagascar hibonite occurrences, this purported Argentinian material is essentially silicate-free and is composed almost entirely of Al-rich oxide minerals. The dominant phase is coarse blocky grossite (dark and lustrous in hand sample). Hosted in the grossite with an ophitic to sub-ophitic texture are abundant coarse laths of one or possibly two additional aluminum-rich oxide phases containing variable proportions of K, Na, Mg and V (reminiscent of diaoyudaoite, and both the K-dominant and Na-dominant compositions are here considered as and normalized as such), as well as abundant hibonite (see BSE images of FKM-202 for a closer look at the mineralogy and textures). The hibonite occurs both as discrete crystals within the grossite and as an intimate intergrowth with the alkali-rich oxide phase(s). In fact, in some cases, it appears as if single crystals compositionally grade between Ca-rich (hibonite) and the alkali-rich zones. The hibonite, nominally U(-), is here instead B(-) with a 2V° < 10°, suggesting either sample strain or an unexpected compositional ordering. Also, unlike that of the Madagascar occurrences, this hibonite is REE-free. Perhaps the most unusual feature of this rock (and the strongest suggestion of a possible slag origin) are the large droplets and finer-scaled arborescent growths of “native” vanadium that are abundantly scattered in the grossite. A closer examination of the droplets shows that in some cases they are multi-phasic, with a low-Fe vanadium central subhedral crystal (with ~1.5 wt% Fe) surrounded by a dendritic growth of a higher-Fe vanadium (with ~6.3 wt% Fe). In addition to the aforementioned minerals, another abundant phase (referred to here as “Al-V-Mg-oxide”) contains major V, Al, Mg and presumably oxygen, along with small amounts of Ti, Ca and Mn. The analysis of this material by EPMA has been challenging and it remains inadequately characterized. WDS scans using TAP, PET, LIF and PC2 crystals show that from carbon onwards, no major elements besides those listed are present (i.e. the material is not a carbide or nitride; H, Li, Be and B can not be ruled out but would seem unexpected). The evidence for oxygen is somewhat ambiguous due to the unfortunate significant overlap of the O Kα X-ray line with the V Lβ and V Lα lines; however, oxygen is believed to be present (and also, if the material is treated as an oxygen-free metal alloy, then the analytical total comes in low at only 67 wt%). However, if the phase is an oxide, there is still some question as to the appropriate valences of the metals. If V and Ti in this material are assigned their typical “reduced” terrestrial valences of V3+ and Ti4+, then the analytical oxide total comes in high at ~108-110% wt% (note that oxygen isn’t directly measured here due to the X-ray interference, but is instead calculated by charge balance). This suggests that these metals could be even more reduced. Hence, to optimize the analytical total and the overall charge balance, the phase is best approximated as containing V2+ and Ti2+, with oxygen treated as slightly non-stoichiometric. Given the reduced nature of the sample, there is some justification in assigning an atypical +2 valence to V and Ti (although the presence of perovskite with Ti4+ complicates the divalent cation hypothesis). In any case, this phase would certainly benefit from additional study. As noted earlier, the entire rock is essentially Si-free. However, there are in places cavities between the larger grossite crystals that are filled with clusters of gehlenite intergrown with perovskite, fluorite and sometimes minor calcite. Overall, whether natural or artificial, this sample has been a fascinating specimen to examine under the microscope and with the microprobe, and the unusual composition has allowed me to better appreciate some of the challenges of analyzing atypical materials. If natural, several of these phases may be new minerals or new geologic occurrences of existing minerals, and warrant further scientific study.

(unpolarized light)

mineral representative mineral compositions in FKM-202
grossite (Ca0.99Na0.01)(Al3.98Si0.01V0.01)O7
perovskite (Ca0.99Na0.01)(Ti0.84Al0.11Zr0.03Si0.02V0.01)O3
hibonite Ca0.99(Al11.33V0.52Mg0.11Ti0.04Si0.01)O19
“K-diaoyudaoite” (?) (K0.46Na0.18Ca0.010.35)(Al10.06Mg0.57VT0.35MnT0.01TiT0.01)O17
diaoyudaoite (?) (Na0.73K0.49)(Al9.99Mg0.59VT0.38MnT0.02TiT0.01Si0.01)O17
“Al-V-Mg-oxide” (?) Ca0.04(Al5.84VT3.04Mg1.94TiT0.10CrT0.05MnT0.04)O13.92 (?)
gehlenite (Ca1.87Na0.11)(Al0.96Mg0.04V0.02)[Si1.09Al0.91O7]

Argentina hibonite and grossite in thin section

same as previous FKM-202 image (under crossed polars).

 




Sannidal Norway chlorapatite and magnesio-hornblende in thin section

sample: FKM-203
locality: Sannidal, Kragerø, Telemark, Norway.
rock type: add rock type.
major mineralogy: specimen acquired for chlorapatite and magnesio-hornblende.
(unpolarized light)

Sannidal Norway chlorapatite and magnesio-hornblende in thin section

same as previous FKM-203 image (under crossed polars).

 




Québec meionite in thin section

sample: FKM-204
locality: unspecified locality from the Grenville geologic province, Québec, Canada.
rock type: scapolite marble.
major mineralogy: specimen acquired for meionite. Based on petrography, meionite and calcite are present. The measured Br content of the scapolite is 17±4 ppm (1σ; n=3) and molar Cl/Br = 691. Br was measured by EPMA by counting Br Kα X-rays on five spectrometers simultaneously (using two LIF and three LLIF crystals) at 25 kV and 500 nA for 240 seconds on-peak. To minimize sample damage under these extreme conditions, the beam was slightly defocused to 5 μm and also slowly moved across the sample. The 1σ detection limit under these conditions is roughly 9 ppm Br.
(unpolarized light)

mineral representative mineral compositions in FKM-204
meionite (Ca1.70Na1.19K0.10Sr0.01Mg0.01)[Si7.25Al4.74O24] . (Ca0.87Na0.07)([CO3]0.69[SO4]0.15Cl0.13)

Québec meionite in thin section

same as previous FKM-204 image (under crossed polars).

 




Madagascar thorianite in thin section

sample: FKM-205
locality: Anosy region, Tuléar province, Malagasy Republic.
rock type: thorianite-spinel-pargasite-diopside marble. Granulite facies metacarbonate.
major mineralogy: Predominately a calcite marble with abundant porphyroblasts of Al-rich diopside (also with up to 2220 ppm Zr), with subordinate porphyroblasts of K-rich fluoro-pargasite (also with up to 1140 ppm Zr) and spinel. Some of the amphibole is enclosed within cpx and suggests an incomplete prograde amphibole-out reaction. In other areas, clots of what appears to be either an unusual VIAl-rich serpentine or a similarly unusual IVAl-free chlorite enclose relict amphibole, and these clots are then curiously rimmed by a relatively unzoned thin band of dissakisite-(Ce), which also occurs as scattered small discrete grains (the grains are irregularly zoned) and as scattered thin discontinuous veinlets elsewhere in the sample. Several coarse veinlets of a low z Ca-Na-aluminosilicate (86-89 wt% analytical totals; presumably a zeolite? [compositionally consistent with wairakite]) traverse the sample. A few large fractured and included zoned REE+Th-bearing fluorapatite crystals are present. Oxides are present as rare scattered baddeleyite and a large thorianite crystal. “Chemical” dating of the thorianite, based on two EPMA spot analyses for Th, U and Pb, gives a mean age of 509±20 Ma, which is consistent with granulite facies metamorphism accompanying the D2 deformation event described for southern Madagascar (for example, see Martelat et al., 2000). This sample bears some similarity to FKM-191 and comes from the same vicinity in Madagascar.
(unpolarized light)

mineral representative mineral compositions in FKM-205
spinel (Mg0.75Fe2+0.23Zn0.02)(Al1.98Fe3+0.02)O4
thorianite (Th0.74UT0.20PbT0.04Ca0.01Ce4+0.01)O2+x
calcite Ca1.00[CO3]
fluorapatite (main) (Ca4.88Ce0.03La0.01Nd0.01Sr0.01)[P2.97Si0.07O12](F0.95Cl0.05[OH]0.01)
fluorapatite
(most REE+Th-rich)
(Ca4.72Ce0.07Y0.04La0.03Nd0.03Pr0.02[HREE]0.02Sm0.01Gd0.01Sr0.01Th0.01)
[P2.71Si0.31O12](F0.77[OH]0.14Cl0.09)
dissakisite-(Ce) Ca1.00(Ce0.46La0.27Ca0.14Nd0.08Pr0.04[M+HREE]0.01)(Al0.96Ti0.03Fe3+0.01)Al1.00
(Mg0.61Fe2+0.30Fe3+0.09)(O0.95F0.05)[Si1.98Al0.02O7][Si1.00O4](OH)
fluoro-pargasite (Na0.57K0.40Ca0.02Sr0.01Ba0.01)Ca2.00(Mg3.58Al0.90Fe3+0.36Ti0.10Fe2+0.06Zr0.01)
[Si5.69Al2.31O22](F0.96[OH]0.82O0.19Cl0.03)
diopside (Ca0.97Na0.02Mg0.01)(Mg0.68Al0.19Fe3+0.08Ti0.03Fe2+0.02Zr0.01)[Si1.68Al0.32O5.99F0.01]
~(Mg3Al2□)[Si4O10](OH)8
VIAl-rich serpentine?
IVAl-free chlorite?
(Ca0.29Na0.01)(Mg2.10Al1.68FeT0.96Zn0.021.23)[Si3.98Al0.01O10]([OH]7.99F0.01)
wairakite? (Ca0.79[Na2]0.22)[Al2.32Si3.65O12] . ~2H2O

Madagascar thorianite in thin section

same as previous FKM-205 image (under crossed polars).

 




California melanite garnet in thin section

sample: FKM-206
locality: New Idria District, Diablo Range, San Benito Co., California, USA.
rock type: add rock type.
major mineralogy: specimen acquired for titaniferous andradite (melanite).
(unpolarized light)

California melanite garnet in thin section

same as previous FKM-206 image (under crossed polars).

 




Khibiny massif Kola Peninsula Russia aenigmatite in thin section

sample: FKM-207
locality: Eveslogchorr Mtn., Khibiny massif, Kola Peninsula, Russia.
rock type: agpaitic nepheline syenite.
major mineralogy: specimen acquired for aenigmatite. Based on petrography, large phenocrysts of aenigmatite, astrophyllite and poikiolitic eudialyte, with smaller crystals of aegirine, all in a medium-fine grained matrix of alkali feldspar and nepheline.
(unpolarized light)

Khibiny massif Kola Peninsula Russia aenigmatite in thin section

same as previous FKM-207 image (under crossed polars).

 




Ivigtut Greenland cryolite and siderite in thin section

sample: FKM-208
locality: Ivigtut cryolite deposit, Ivittuut, Arsuk Fjord, Sermersooq, Greenland.
rock type: granite pegmatite-associated fluoride-rich segregation (mined out in 1987).
major mineralogy: Based on petrography, almost entirely massive cryolite, with scattered large crystals of siderite (partially altered to hematite) and subordinate quartz, sphalerite and galena. Although at first glance the cryolite appears isotropic under crossed polars, it is in fact weakly birefringent (δ ≈ 0.001) and displays complex twinning and intergrowths (best observed in the lower right side of the image).
(unpolarized light)

Ivigtut Greenland cryolite and siderite in thin section

same as previous FKM-208 image (under crossed polars).

 




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sample: FKM-209
locality: Faria claim, Golconda district, Governador Valadares, Minas Gerais, Brazil.
rock type: granite pegmatite.
major mineralogy: specimen acquired for fluorapatite, betrandite, albit and chlorite.
(unpolarized light)

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same as previous FKM-209 image (under crossed polars).

 




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sample: FKM-210
locality: Brumado, Bahia, Brazil.
rock type: uvite-magnesite marble. Metamorphosed Mg-metasomatite(?)
major mineralogy: specimen acquired for uvite and magnesite.
(unpolarized light)

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same as previous FKM-210 image (under crossed polars).

 




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sample: FKM-211
locality: Kipawa alkaline complex, Les Lacs-du-Témiscamingue, Abitibi-Témiscamingue, Québec, Canada.
rock type: metamorphosed alkali syenite.
major mineralogy: specimen acquired for gittinsite, vlasovite and eudialyte.
(unpolarized light)

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same as previous FKM-211 image (under crossed polars).

 




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sample: FKM-212 (billet courtesy of E. Grew, Univ. Maine; sample #2344D)
locality: Mount Riiser-Larsen, Napier Complex, Enderby Land, Antarctica.
rock type: UHT metapelitic granulite.
major mineralogy: specimen acquired for osumilite and cordierite.
(unpolarized light)

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same as previous FKM-212 image (under crossed polars).

 




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sample: FKM-213 (billet courtesy of Z. Mcintire, Univ. Washington)
locality: near Erbareti, Vercelli province, Piemonte, Italy.
rock type: charnockite.
major mineralogy: specimen acquired for orthopyroxene.
(unpolarized light)

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same as previous FKM-213 image (under crossed polars).

 




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sample: FKM-214
locality: Hålsjöberg, Torsby, Värmland, Sweden.
rock type: test.
major mineralogy: specimen acquired for wagnerite and lazulite.
(unpolarized light)

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same as previous FKM-214 image (under crossed polars).

 




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sample: FKM-215
locality: Saranovskii mine, Saranovskaya village, Permskaya Oblast’ (middle Ural Mtns. region), Russia.
rock type: hydrothermally altered and metamorphosed chromitite.
major mineralogy: specimen acquired for chromian amesite and chromite.
(unpolarized light)

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same as previous FKM-215 image (under crossed polars).

 




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sample: FKM-216
locality: Bald Knob deposit, Bald Knob, Sparta, Alleghany Co., North Carolina, USA.
rock type: test.
major mineralogy: specimen acquired for kellyite, galaxite and kutnohorite.
(unpolarized light)

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same as previous FKM-216 image (under crossed polars).

 




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sample: FKM-217
locality: Tanco pegmatite mine, Bernic Lake, Lac-du-Bonnet area, Manitoba, Canada.
rock type: test.
major mineralogy: specimen acquired for wodginite, microcline and lithian muscovite.
(unpolarized light)

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same as previous FKM-217 image (under crossed polars).

 




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sample: FKM-218
locality: Üdersdorf, Daun, Eifel, Rhineland-Palatinate, Germany.
rock type: test.
major mineralogy: specimen acquired for perovskite, augite and nepheline.
(unpolarized light)

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same as previous FKM-218 image (under crossed polars).

 




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sample: FKM-219
locality: Anna mine, Horní Planá (by Mariánské Lázně), Karlovy Vary region, Bohemia, Czech Republic.
rock type: test.
major mineralogy: specimen acquired for roscoelite.
(unpolarized light)

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same as previous FKM-219 image (under crossed polars).

 




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sample: FKM-220
locality: Pacific Limestone Products Quarry (Kalkar Quarry), Santa Cruz, Santa Cruz Co., California, USA.
rock type: test.
major mineralogy: specimen acquired for pabstite.
(unpolarized light)

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same as previous FKM-220 image (under crossed polars).

 




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sample: FKM-221
locality: Little Green Monster mine, Clay Canyon, Fairfield, Utah Co., Utah, USA.
rock type: phosphatic nodules in limestone.
major mineralogy: specimen acquired for variscite, crandallite, wardite and kolbeckite.
(unpolarized light)

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same as previous FKM-221 image (under crossed polars).

 




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sample: FKM-222
locality: near Mama River, Buryatia, Pribaikal’e, Eastern Siberian region, Russia.
rock type: test.
major mineralogy: specimen acquired for lazulite and muscovite.
(unpolarized light)

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same as previous FKM-222 image (under crossed polars).

 




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sample: FKM-223
locality: Kuannersuit Plateau (Kvanefjeld), Ilímaussaq complex, Narsaq, Kujalleq, Greenland.
rock type: test.
major mineralogy: specimen acquired for neptunite.
(unpolarized light)

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same as previous FKM-223 image (under crossed polars).

 




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sample: FKM-224
locality: Pedra Balão outcrops, Poços de Caldas, Poços de Caldas alkaline complex, Minas Gerais, Brazil.
rock type: khibinite.
major mineralogy: specimen acquired for manganoeudialyte.
(unpolarized light)

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same as previous FKM-224 image (under crossed polars).

 




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sample: FKM-225
locality: Kaznakhtinskii massif, Ust’-Koksa district, Gorno-Altayskaya Autonomous Oblast’, Western Siberian region, Russia.
rock type: test.
major mineralogy: specimen acquired for chromian iowaite and serpentine.
(unpolarized light)

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same as previous FKM-225 image (under crossed polars).

 




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sample: FKM-226
locality: Khungtukun Massif, Malaya Romanikha River, Khatanga, Taimyr Peninsula, Taymyrskiy Autonomous Okrug, Eastern Siberian region, Russia.
rock type: intrusion of gabbro through a coal seam.
major mineralogy: specimen acquired for native iron, cohenite, plagioclase and pyroxene.
(unpolarized light)

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same as previous FKM-226 image (under crossed polars).

 




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sample: FKM-227
locality: Eveslogchorr Mtn., Khibiny massif, Kola Peninsula, Russia.
rock type: agpaitic nepheline syenite.
major mineralogy: specimen acquired for astrophyllite.
(unpolarized light)

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same as previous FKM-227 image (under crossed polars).

 




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sample: FKM-228
locality: Varenche mine, Saint-Barthélemy, Nus, Aosta Valley, Italy.
rock type: test.
major mineralogy: specimen acquired for manganberzeliite.
(unpolarized light)

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same as previous FKM-228 image (under crossed polars).

 




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sample: FKM-229 (billet courtesy of J. Worthington, Univ. Arizona; sample 13P121)
locality: Panj River gorge, ~5 km N of Vogde, Tajikistan.
rock type: high grade melanosomic restite in migmatitic leucogranite.
major mineralogy: specimen acquired for garnet.
(unpolarized light)

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same as previous FKM-229 image (under crossed polars).

 




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sample: FKM-230
locality: Madagascar (a more specific locality is not identified, but the sample resembles material from the Ampanihy rhodonite deposit.
rock type: test.
major mineralogy: specimen acquired for rhodonite, Mn-oxides and spessartine.
(unpolarized light)

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same as previous FKM-230 image (under crossed polars).

 




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sample: FKM-231
locality: Mendes Pimentel, Minas Gerais, Brazil.
rock type: test.
major mineralogy: specimen acquired for brazilianite.
(unpolarized light)

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same as previous FKM-231 image (under crossed polars).

 




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sample: FKM-232
locality: stated by the dealer as “southern India”; however, the material has been alternatively reported as being from northeastern India (reportedly from the Ganjam area, Orissa state).
rock type: test.
major mineralogy: specimen acquired for corundum and cordierite.
(unpolarized light)

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same as previous FKM-232 image (under crossed polars).

 




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sample: FKM-233
locality: stated by the dealer as “southern India”. This material is widely available online as tumbled stones (notably among the “healing crystal” community), but frustratingly, no one seems to have a more specific locality than just “India”. This material is too popular and too distinctive to remain a mystery; I will eventually figure this one out!
rock type: test.
major mineralogy: specimen acquired for spinel.
(unpolarized light)

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same as previous FKM-233 image (under crossed polars).

 




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sample: FKM-234
locality: Russia (a more specific locality is not identified, but the sample resembles the “Orlets”-type material from the famous rhodonite mines of the Ekaterinburg area, Middle Urals).
rock type: test.
major mineralogy: specimen acquired for rhodonite.
(unpolarized light)

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same as previous FKM-234 image (under crossed polars).

 




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sample: FKM-235
locality: Summit Rock, Klamath Co., Oregon, USA.
rock type: andesite.
major mineralogy: specimen acquired for fayalite (in lithophysae).
(unpolarized light)

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same as previous FKM-235 image (under crossed polars).

 




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sample: FKM-236
locality: Jakobsberg Mine, Jakobsberg ore field, Nordmark district, Filipstad, Värmland, Sweden.
rock type: test.
major mineralogy: specimen acquired for barylite, hausmannite and calcite
(unpolarized light)

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same as previous FKM-236 image (under crossed polars).

 




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sample: FKM-237
locality: Magnet Cove, Hot Spring Co., Arkansas, USA.
rock type: test.
major mineralogy: specimen acquired for aegirine.
(unpolarized light)

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same as previous FKM-237 image (under crossed polars).

 




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sample: FKM-238
locality: Pacific Limestone Products Quarry (Kalkar Quarry), Santa Cruz, Santa Cruz Co., California, USA.
rock type: test.
major mineralogy: specimen acquired for gersdorffite and molybdenite.
(unpolarized light)

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same as previous FKM-238 image (under crossed polars).

 




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sample: FKM-239
locality: Raidlgraben, Fritzbach valley, Pöham, Werfen, Salzburg, Austria.
rock type: test.
major mineralogy: specimen acquired for lazulite.
(unpolarized light)

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same as previous FKM-239 image (under crossed polars).

 




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sample: FKM-240
locality: Obsidian Cliffs, North Sister Mountain, McKenzie Pass, Lane Co., Oregon, USA.
rock type: test.
major mineralogy: specimen acquired for osumilite.
(unpolarized light)

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same as previous FKM-240 image (under crossed polars).

 




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sample: FKM-241
locality: Lågendalen, Hedrum, Larvik, Vestfold, Norway.
rock type: test.
major mineralogy: specimen acquired for catapleiite.
(unpolarized light)

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same as previous FKM-241 image (under crossed polars).

 




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sample: FKM-242
locality: Nordmark Odal Field, Filipstad, Värmland, Sweden (reportedly from the Kitteln ‘2’ mine).
rock type: test.
major mineralogy: specimen acquired for orthopinakiolite.
(unpolarized light)

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same as previous FKM-242 image (under crossed polars).

 




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sample: FKM-243
locality: Långban, Filipstad, Värmland, Sweden.
rock type: test.
major mineralogy: specimen acquired for caryinite.
(unpolarized light)

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same as previous FKM-243 image (under crossed polars).

 




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sample: FKM-244
locality: Gem mine, San Benito River headwaters area, New Idria district, San Benito Co., California, USA.
rock type: test.
major mineralogy: specimen acquired for benitoite, neptunite and natrolite.
(unpolarized light)

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same as previous FKM-244 image (under crossed polars).

 




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sample: FKM-245 (billet from the Univ. Arizona petrology collection, sample Wards 22)
locality: Salem Neck, Essex Co., Massachusetts, USA.
rock type: nepheline syenite.
major mineralogy: specimen acquired for nepheline and biotite.
(unpolarized light)

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same as previous FKM-245 image (under crossed polars).

 




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sample: FKM-246
locality: Rapid Creek, Dawson Mining District, Yukon, Canada.
rock type: metasomatized sedimentary phosphorite.
major mineralogy: specimen acquired for lazulite, wardite and augelite.
(unpolarized light)

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same as previous FKM-246 image (under crossed polars).

 




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sample: FKM-247
locality: Iodake, Satsuma-Ioujima, Mishima village, Kagoshima Prefecture, Nansei Archipelago, Kyushu region, Japan.
rock type: test.
major mineralogy: specimen acquired for roedderite.
(unpolarized light)

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same as previous FKM-247 image (under crossed polars).

 




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sample: FKM-248 (billet from the Univ. Arizona petrology collection, sample Wards 45)
locality: Portland Point, Tompkins Co., New York, USA.
rock type: mica peridotite.
major mineralogy: specimen acquired for phlogopite and garnet.
(unpolarized light)

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same as previous FKM-248 image (under crossed polars).

 




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sample: FKM-249 (billet from the Univ. Arizona petrology collection, sample Wards 23)
locality: near Red Hill, Moultonborough, Carroll Co., New Hampshire, USA.
rock type: nepheline sodalite syenite.
major mineralogy: specimen acquired for nepheline, sodalite and aegirine.
(unpolarized light)

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same as previous FKM-249 image (under crossed polars).

 




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sample: FKM-250 (billet from the Univ. Arizona petrology collection, sample Wards 46)
locality: Murfreesboro, Pike Co., Arkansas, USA.
rock type: mica augite peridotite.
major mineralogy: specimen acquired for phlogopite, augite and olivine.
(unpolarized light)

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same as previous FKM-250 image (under crossed polars).

 




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sample: FKM-251 (billet from the Univ. Arizona petrology collection, sample Wards 32)
locality: Mont Saint-Gregoire (Mont Johnson; Monoir), Le Haut-Richelieu RCM, Montérégie, Québec, Canada.
rock type: essexite.
major mineralogy: specimen acquired for nepheline.
(unpolarized light)

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same as previous FKM-251 image (under crossed polars).

 




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sample: FKM-252
locality: reportedly from “Kiev, Ukraine”, but this locality is not entirely consistent with the sample’s purported mineralogy/petrology.
rock type: test.
major mineralogy: specimen acquired for boracite and chromite (!)
(unpolarized light)

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same as previous FKM-252 image (under crossed polars).

 




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sample: FKM-253
locality: Darai-Pioz glacier, Alai range, Tien Shan Mtns., Tajikistan.
rock type: highly-evolved B-rich alkali granite.
major mineralogy: specimen acquired for stillwellite-(Ce).
(unpolarized light)

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same as previous FKM-253 image (under crossed polars).

 




Bad Harzburg Germany mica peridotite glimmerite in thin section

sample: K-65 (covered and yellowing thin section from Univ. Arizona petrology collection [unfortunately, the original billet & hand sample appear to be lost], Krantz collection, sample K-65)
locality: Kaltes Tal, Bad Harzburg, Harz Mtn. region, Niedersachsen, Germany.
rock type: mica peridotite (as small lenses in norite). Also known locally as “glimmerite”.
major mineralogy: Based on petrography, predominately forsterite and red Ti-rich(?) biotite, with gray spinel and minor oxide (believed to be ilmenite).
(unpolarized light)

Bad Harzburg Germany mica peridotite glimmerite in thin section

same as previous K-65 image (under crossed polars).

 


previous page (samples FKM-101 to FKM-200)

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This “add photo(s)” image is just a placeholder in advance of adding new samples, so check back periodically to see my progress.