phyllosilicates in thin section


Check out the video atlas of minerals in thin section introduction page for some background on how these videos were prepared and processed, and for additional useful information on the included table content, the search tab, and other user-adjustable features. There is also an accompanying illustration to assist viewers with determining 2V° values from the BxA or optic axis figures in the “optic figures” videos.

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mineral PPL (lower
polar rotation)
(stage rotation)
(stage rotation)
optic figure
(stage rotation)
amesite (FKM-215):
Cr-bearing amesite serpentine in hydrothermally altered chromitite, with magnesio-chromite/chromite
kellyite (FKM-243):
kellyite (serpentine group) in amphibolite facies calcareous meta-Mn-metasomatite, with kutnohorite, alleghanyite and galaxite spinel (note: thin section is cut somewhat thin)
pyrophyllite (FKM-167):
pyrophyllite in a meta-“advanced argillic” metasomatite, with kyanite
talc (FKM-101):
talc in greenschist facies meta-ultramafic, with clinochlore chlorite
muscovite (FKM-100):
phengitic muscovite (dioctahedral mica) in blueschist, with glaucophane amphibole, epidote and quartz
muscovite (FKM-292):
muscovite (dioctahedral mica) in tourmaline-bearing mica schist
muscovite (FKM-312):
Cr-bearing (0.10 Cr apfu) muscovite (“fuchsite”; dioctahedral mica) in biotite-zone metapelite schist, with quartz and plagioclase feldspar
aluminoceladonite (FKM-171):
Mn-bearing (0.12 MnT apfu) aluminoceladonite (dioctahedral mica) in meta-Mn-exhalite, with phlogopite mica and alkali feldspar
chromceladonite/ “vanadoceladonite” (FKM-257):
intergrown Cr-dominant (up to 1.02 Cr apfu) and V-dominant (up to 0.69 V apfu) celadonite group dioctahedral micas in U-V-metasomatite, with quartz and barite
polylithionite (FKM-430):
polylithionite (2.00 F apfu; by stoichiometry & charge balance: 1.86 Li apfu) lepidolite mica in Cs-B-Li-enriched granite, with quartz and alkali feldspar
phlogopite (FKM-11):
phlogopite (trioctahedral mica) in granulite facies meta-blackwall, with sapphirine
phlogopite (FKM-41):
zoned phlogopite (trioctahedral mica) in sövite carbonatite, with diopside clinopyroxene and calcite
phlogopite (FKM-56):
zoned phlogopite (trioctahedral mica) in haüyne melilitolite (“okaite”), with calcite, melilite and magnetite
phlogopite (FKM-156):
phlogopite (trioctahedral mica) in greenschist facies meta-blackwall, with chlorite
phlogopite (FKM-171):
Mn-bearing (0.39 MnT apfu) phlogopite (trioctahedral mica) in meta-Mn-exhalite, with alkali feldspar and a hollandite-group oxide
phlogopite (FKM-193):
Mn-bearing (~0.10 Mn2+ apfu) phlogopite (trioctahedral mica) in high grade calcareous Ba-Mn-metasomatite, with calcite, melanotekite and cymrite
phlogopite (FKM-295):
Ba-bearing (0.16 Ba apfu; 2.53 Mg apfu) phlogopite (trioctahedral mica) in high grade B-bearing skarn, with serendibite, pargasite amphibole and diopside clinopyroxene
phlogopite (FKM-298):
zoned phlogopite (trioctahedral mica) in sövite carbonatite, with apatite, magnetite and calcite
phlogopite (FKM-350):
phlogopite (trioctahedral mica) showing abundant pleochroic halos, in granite-associated phlogopite skarn with fluorite and calcite
biotite (FKM-46):
biotite (trioctahedral mica) in granulite facies B-bearing metapelite, with garnet, K-feldspar and partially altered cordierite
biotite (FKM-78):
biotite (trioctahedral mica) in high grade low-silica feldspathic gneiss, with orthoclase mesoperthite
biotite (FKM-401):
biotite (trioctahedral mica) in Be-enriched Fe-metasomatite, with ferro-pargasite amphibole
biotite (K-65):
red biotite (presumably Mg- and Ti-rich; trioctahedral mica) in mica peridotite, with spinel and forsterite olivine (covered thin section)
tainiolite (FKM-256):
tainiolite (trioctahedral mica) in albitized granite, with aegirine-augite, quartz and alkali feldspar
margarite (FKM-322):
beryllian margarite in altered pegmatite
clintonite (FKM-389):
clintonite in high-grade skarn, with monticellite, calcite and grossular
gillespite (FKM-53b):
gillespite in Ba-metasomatite, with quartz, cerchiaraite-(Fe) and titantaramellite
presumably U(-) but no optic figure available
clinochlore (FKM-101):
clinochlore chlorite in greenschist facies meta-ultramafic, with talc
clinochlore (FKM-156):
clinochlore chlorite in greenschist facies meta-blackwall, with phlogopite and chrysoberyl
clinochlore (FKM-290):
clinochlore chlorite in high pressure meta-gabbroid, with epidote and zoisite
high-Cr clinochlore (FKM-340):
high-Cr clinochlore (“kammererite”?; up to 0.67 Cr apfu) in metasomatized chromatite, with low-Cr chlorite and chromite (sensu lato)
no optic figure of useful quality was available
low-Cr clinochlore (FKM-340):
low-Cr clinochlore (“kammererite”?; 0.21 Cr apfu) in metasomatized chromatite, with high-Cr chlorite and chromite (sensu lato)
pyrosmalite-(Mn) (FKM-190): anomalously weakly biaxial Fe-bearing pyrosmalite-(Mn) (4.06 Mn2+ apfu; 3.62 Fe2+ apfu; formerly “manganpyrosmalite”) in high grade meta-Mn-metasomatite, with rhodochrosite, quartz and pyroxmangite
stilpnomelane (FKM-15):
stilpnomelane in blueschist facies ferruginous meta-quartzite, with quartz and spessartine garnet
presumably B(-)
but no optic figure available
stilpnomelane (FKM-141):
stilpnomelane in blueschist facies Na-metasomatized meta-Fe-exhalite, with riebeckite
zussmanite (FKM-147):
zussmanite in blueschist facies ferruginous metaquartzite, with deerite and quartz
sanbornite (FKM-53):
sanbornite in Ba-Ti-metasomatite, with quartz, titantaramellite and actinolite
cavansite (FKM-170):
cavansite in zeolite facies altered basalt, with stilbite
delhayelite (FKM-407):
delhayelite in agpaitic nepheline syenite, with aenigmatite, barytolamprophyllite and nepheline

non-silicates in thin section

nesosilicates in thin section

sorosilicates and cyclosilicates in thin section

single chain inosilicates in thin section

double chain and more complex inosilicates in thin section

tectosilicates and miscellaneous silicates in thin section