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The Vimeo-hosted versions of these video are also search-engine discoverable, and can be found by searching for the term “thin section” coupled with the sample number (e.g. “thin section FKM-49”), with or without also including the accompanying mineral name. YouTube-hosted versions of these videos are no longer search-engine discoverable (in protest of YouTube polluting even short educational videos with non-optional ads… grrr!), but can still be found organized in playlists on my rockPTX YouTube channel.
mineral | PPL (lower polar rotation) |
PPL (stage rotation) |
XP (stage rotation) |
optic figure (stage rotation) |
---|---|---|---|---|
zincite (FKM-20): zincite in high grade calcareous Zn-Mn metasomatite, with calcite and franklinite |
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corundum (FKM-78): corundum (slightly thick due to extreme hardness) in high grade low-silica feldspathic gneiss, with biotite, plagioclase and alkali feldspar |
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corundum (FKM-290): Cr-bearing (0.01 Cr apfu) ruby variety of corundum (slightly thick due to extreme hardness) in high pressure meta-gabbroid, with epidote and zoisite (note: optic axis figure is far off-center due to lack of ideally-oriented crystals) |
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rutile (FKM-273): coarse rutile in phosphate-rich meta-advanced-argillite, with burangaite and berlinite |
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baddeleyite (FKM-191): baddeleyite in granulite facies high-alumina metasomatic “plagioclasite”, with anorthite feldspar and corundum |
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spinel (FKM-106): Cr-bearing (0.77 Mg apfu; 0.24 Cr apfu) spinel in carbonatite-associated damtjernite dike, with calcite, serpentine, amphibole and phlogopite |
isotropic | |||
spinel (FKM-162): Cr-bearing (0.78 Mg apfu; 0.18 Cr apfu) spinel in basalt-hosted spinel peridotite xenolith, with forsterite olivine and Cr-bearing diopside clinopyroxene |
isotropic | |||
spinel (FKM-191): spinel in granulite facies aluminous calc-silicate, with anorthite |
isotropic | |||
spinel (FKM-290): Cr-bearing (0.51 Mg apfu; 0.17 Cr apfu) spinel in high pressure meta-gabbroid, with Cr-bearing pargasite amphibole, corundum, zoisite and aluminous vermiculite clay |
isotropic | |||
hercynite (FKM-46): hercynite (spinel group) in granulite facies B-bearing metapelite, with partially altered cordierite |
isotropic | |||
hercynite (FKM-263): hercynite (spinel group) in Al-rich “calc-skarnoid”, with vesuvianite and calcite |
isotropic | |||
gahnite (FKM-12): gahnite (spinel group) in high grade Zn-bearing meta-quartzite, with quartz |
isotropic | |||
gahnite (FKM-48): gahnite (spinel group) in high grade calcareous Zn-Mn metasomatite, with franklinite and tephroite |
isotropic | |||
chrysoberyl (FKM-156): chrysoberyl in greenschist facies meta-blackwall, with phlogopite and chlorite |
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perovskite (FKM-404): perovskite in sövite carbonatite, with apatite, magnetite and calcite |
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srebrodolskite (FKM-383): srebrodolskite (1.27 Fe3+ apfu) in sanidinite facies paralava, with gehlenite and larnite |
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grossite (FKM-202): pleochroic V-bearing (0.01 V apfu) grossite in probable slag, with hibonite, intergrown K- & Na-dominant diaoyudaoite(?) and vanadium |
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hibonite (FKM-191): hibonite in granulite facies aluminous calc-silicate, with spinel, anorthite plagioclase and corundum |
presumably U(-) but no optic figure available |
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hibonite (FKM-263): hibonite in Al-rich “calc-skarnoid”, with vesuvianite and calcite |
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“cobaltohögbomite-2N2S“ (FKM-75): pleochroic violet Co-dominant (0.88 Co apfu) högbomite (“cobaltohögbomite”) in amphibolite facies meta-ferrolite, with quartz and magnetite (100X) |
presumably U(-) but no optic figure available |
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diaoyudaoite(?) (FKM-202): intergrown mixed K- and Na-dominant diaoyudaoite(?) in probable slag, with hibonite, grossite and vanadium |
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wodginite (FKM-217): wodginite in granite pegmatite, with albite and Li-bearing mica |
presumably biaxial but no optic figure available |
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hydroxycalciopyrochlore (FKM-41): zoned pyrochlore in sövite carbonatite, with apatite, diopside clinopyroxene and calcite |
isotropic | |||
“pyrochlore” (FKM-432): U-rich (to 0.33 U apfu) zoned “pyrochlore” (high-z main core hydroxynatropyrochlore with patchy low-z fluorocalciopyrochlore, all rimmed by mod-z hydroxycalciopyrochlore) in evolved Cs-Li-B granite, with sogdianite, quartz and albite (100X + condenser lens) |
isotropic | |||
fluorcalciomicrolite (FKM-104): fluorocalciomicrolite in Li-Ta-enriched granite pegmatite, with Li-muscovite mica and microcline K-feldspar |
isotropic | |||
fluorite (FKM-146): color-zoned fluorite in agpaitic nepheline syenite (“lakarpite”), with arfvedsonite amphibole, nepheline and rosenbuschite |
isotropic | |||
fluorite (FKM-315): color-zoned fluorite in metamorposed agpaitic syenite, with alkali feldspar (microcline host & coarse albite patches) and omphacite/aegirine-augite clinopyroxene |
isotropic | |||
fluorite (FKM-401): color-zoned fluorite in Be-enriched Fe-metasomatite, with biotite and minor ferro-pargasite amphibole |
isotropic | |||
cryolite (FKM-208): cryolite in F-rich segregation in granite, with quartz, siderite and Fe-oxyhydroxide |
presumably B(+), but the birefringence was too low to obtain a useable figure | |||
magnesite (FKM-210): magnesite in Mg-metasomatite |
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calcite (FKM-298): anomalously biaxial calcite in sövite carbonatite, with fluorapatite. The slight deviation from uniaxial optics is presumably due to crystal strain |
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rhodochrosite (FKM-190): rhodochrosite in high grade meta-Mn-metasomatite, with proto-ferro-suenoite (formerly “proto-mangano-ferro-anthophyllite”) amphibole, quartz, spessartine garnet and pyroxmangite |
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siderite (FKM-208): siderite in F-rich segregation in granite, with quartz, cryolite and Fe-oxyhydroxide (as an alteration of siderite) |
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dolomite (FKM-115): Fe-bearing dolomite (0.09 Fe apfu in greenschist facies meta-altered-ultramafic, with clinochlore chlorite |
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dolomite (FKM-426): dolomite in high-grade B-bearing metacarbonate, with [associated minerals] |
video pending | video pending | video pending | video pending |
ankerite (FKM-66): zoned ankerite-dolomite in carbonatite, with sodalite |
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azurite (FKM-351): azurite in altered rhyolite, with tyrolite (and epoxy-filled open space) |
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dawsonite (FKM-66): dawsonite in carbonatite, with sodalite and zoned ankerite-dolomite |
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stichtite (FKM-197): stichtite (perhaps admixed with optically-similar barbertonite) in Cr-bearing serpentinite, with serpentine |
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ludwigite (FKM-426): ludwigite in high-grade B-bearing metacarbonate, with “hydroxylhumite” and dolomite |
presumably B(+) but crystals were too dark to obtain an optic figure |
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fredrikssonite (FKM-242): fredrikssonite in high-grade Mn-metasomatite, with calcite/dolomite, adelite, and opaque jacobsite-Q (note: thin section is cut somewhat thin) |
presumably B(+) but crystals were too dark to obtain an optic figure |
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warwickite (FKM-184): warwickite in granulite facies B-bearing meta-carbonate, with calcite/dolomite and clinohumite (note: thin section is cut substantially thin) |
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henmilite (FKM-377): henmilite in sanidinite facies B-bearing meta-carbonate, with undifferentiated Ca borates |
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olshanskyite (FKM-284): olshanskyite in borate skarn, with sakhaite and additional undifferentiated hydrous borates |
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sakhaite (FKM-284): sakhaite in borate skarn, with coarse veinlet of olshanskyite and additional undifferentiated hydrous borates |
isotropic | |||
barite (FKM-412): barite in meta-Mn-metasomatite, with [associated minerals] |
video pending | video pending | video pending | video pending |
caryinite (FKM-353): caryinite in high-grade Mn-metasomatite, with manganberzeliite, tephroite and calcite |
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manganberzeliite (FKM-228): manganberzeliite in metasomatized meta-Mn-exhalite, with calcite and quartz |
isotropic (some grains anomalously birefringent) | |||
schäferite (FKM-392): schäferite in historic anthropogenic slag, with plagioclase (to be confirmed) |
isotropic (some areas anomalously birefringent) | |||
berlinite (FKM-273): berlinite (isostructural with quartz and optically similar, but with low negative relief) in phosphate-rich meta-advanced-argillite, with trolleite and kyanite that is rimmed by other Al-phosphates |
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adelite (FKM-242): adelite in high-grade Mn-metasomatite, with dolomite, hydroxylclinohumite, and opaque jacobsite-Q (note: thin section is cut somewhat thin) |
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wagnerite (FKM-214): wagnerite in phosphate-rich meta-advanced-argillite, with lazulite and quartz |
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fluorapatite (FKM-41): apatite in sövite carbonatite, with diopside clinopyroxene and calcite (apparent weak “pleochroism” due to accidental stray polarization) |
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hydroxylapatite (FKM-404): hydroxylapatite in sövite carbonatite, with kimzeyite garnet, perovskite and calcite |
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lazulite (FKM-163): lazulite in a meta-“advanced argillic” metasomatite, with andalusite, kyanite, muscovite and quartz |
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lazulite (FKM-214): lazulite in phosphate-rich meta-advanced-argillite, with wagnerite, kyanite and quartz |
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scorzalite (FKM-273): atypical pleochroism scheme (and also anomalously low 2V°) low-Mg (0.02 to 0.07 Mg apfu) scorzalite in phosphate-rich meta-advanced-argillite, with kyanite and trolleite |
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trolleite (FKM-273): trolleite in phosphate-rich meta-advanced-argillite |
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burangaite (FKM-273): burangaite in phosphate-rich meta-advanced-argillite, with kyanite, trolleite, berlinite and additional Al-rich phosphates |
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vivianite (FKM-385): vivianite in phosphate-rich granite, with additional Fe-phosphates, muscovite, quartz and zinconigerite-2N1S |
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frondelite-[manganoan rockbridgeite] ss (FKM-434): frondelite (0.76 Mn2+ apfu; 0.13 Fe2+ apfu) to Mn-rich rockbridgeite (0.50 Fe2+ apfu; 0.47 Mn2+ apfu) in phosphate-rich granite, with “ferrisicklerite” and additional Fe-(Mn)-phosphates |
no crystals were found that provided good optic figures | |||
“ferrisicklerite” (FKM-434): intermediate compositions along the triphylite-heterosite join (variable composition; one spot: 0.67 Li; 0.27 Fe3+ apfu; 0.48 Fe2+ apfu; 0.22 Mn2+ apfu) in phosphate-rich granite, with additional Fe-(Mn)-phosphates |
no crystals were found that provided good optic figures | |||
leucophosphite (FKM-434): leucophosphite in phosphate-rich granite, with additional Fe-(Mn)-phosphates |
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jahnsite-(CaMnMg) (FKM-434): zoned crystals from minor whiteite-(CaMnMg) cores to predominately jahnsite-(CaMnMg) mantles in phosphate-rich granite, with leucophosphite and frondelite/Mn-rich rockbridgeite |
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sorosilicates and cyclosilicates in thin section
single chain inosilicates in thin section
double chain and more complex inosilicates in thin section
phyllosilicates in thin section
tectosilicates and miscellaneous silicates in thin section