sorosilicates and cyclosilicates in thin section


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mineral PPL (lower
polar rotation)
(stage rotation)
(stage rotation)
optic figure
(stage rotation)
melilite (FKM-56):
Na-rich melilite (0.36 Na apfu; 0.46 Mg apfu) in haüyne melilitolite (“okaite”), with calcite, phlogopite trioctahedral mica, apatite and magnetite
melilite (FKM-114):
Na-rich melilite (0.36 Na apfu; 0.53 Mg apfu) in olivine melilitite, with forsterite olivine, diopside clinopyroxene and nepheline
åkermanite (FKM-262):
åkermanite-dominant (0.23 Al apfu; 0.67 Mg apfu; 0.25 Na apfu) melilite in alkaline ultramafic intrusive, with diopside clinopyroxene
gehlenite (FKM-271):
Fe-rich gehlenite-dominant (0.30 Fe3+ apfu) melilite in pyrometamorphic sanidinite facies phosphatic metacarbonate, with apatite and brown cebollite (note: thin section is slightly thick)
hardystonite (FKM-303):
zoned hardystonite (main: 0.09 [Al+Mg+Fe] apfu & 0.06 Na apfu; patchy: 0.05 [Sr+Pb] apfu) in high-grade Mn-Zn metasomatite, with bustamite and andradite garnet
bertrandite (FKM-209):
open-space filling bertrandite sheaves in granite pegmatite, with fluorapatite
bertrandite (FKM-291):
bertrandite in skarn, with quartz and carbonate
tinzenite (FKM-185):
tinzenite (axinite group) in metasomatized meta-Mn-exhalite, with quartz
lawsonite (FKM-109):
lawsonite in blueschist facies metabasite, with garnet, glaucophane amphibole, white mica and chlorite
niocalite (FKM-57):
niocalite in sövite carbonatite, with calcite and apatite
hiortdahlite (FKM-315):
hiortdahlite in metamorposed agpaitic syenite, with fluorite, alkali feldspar (primarily microcline) and zoned omphacite/aegirine-augite clinopyroxene
mosandrite-(Ce) (FKM-65):
mosandrite-(Ce) in metamorposed agpaitic syenite, with microcline K-feldspar, eudialyte and fluoro-richterite amphibole
mosandrite-(Ce) (FKM-145):
mosandrite-(Ce) in agpaitic nepheline syenite, with arfvedsonite amphibole, aegirine clinopyroxene, eudialyte and nepheline
lamprophyllite (FKM-17):
lamprophyllite in nepheline syenite, with aegirine, nepheline and microcline
melanotekite (FKM-86):
melanotekite in high grade calcareous Ba-Mn-metasomatite, with phlogopite trioctahedral mica
strontioruizite (FKM-173):
orange strontioruizite (1.82 Sr apfu) in Mn-metasomatite, with aluminosugilite/sugilite ss, quartz, pectolite and fine-grained aegirine.
prismatine (FKM-59):
prismatine (kornerupine group) in granulite facies B-bearing metapelite, with plagioclase feldspar and tourmaline
allanite-(Ce) (FKM-131):
allanite-(Ce) (epidote group) in calc-silicate REE-U metasomatite, with andradite garnet
ferriallanite-(Ce) (FKM-89):
anomalously low-2V° ferriallanite-(Ce) (epidote group) in REE-metasomatite, with cerite-(Ce) and tremolite amphibole
dollaseite-(Ce) (FKM-188):
anomalously high-2V° dollaseite-(Ce) (1.69 [M1+M3]Mg apfu; epidote group) in calcareous REE-metasomatite, with tremolite amphibole and calcite
epidote (FKM-4):
epidote (0.50 Fe3+ apfu; epidote group) in blueschist, with glaucophane amphibole
epidote (FKM-44):
zoned epidote (0.53 Fe3+ apfu core; 0.99 Fe3+ apfu rim; epidote group) in greenschist facies Na-Ca metasomatite, with quartz and chlorite
hancockite (FKM-88):
hancockite (epidote group) in high grade calcareous Zn-Mn-Pb-Ba metasomatite, with barite
piemontite (FKM-2):
Sr-bearing (0.36 Sr apfu) piemontite (epidote group) in meta-Mn-exhalite, with titanite and quartz
mukhinite (FKM-332):
mukhinite (epidote group) in metasomatized low-grade meta-“oil shale”, with tremolite, “chabazite”? and bitumen?
clinozoisite (FKM-168):
clinozoisite (0.32 Fe3+ apfu; epidote group) in calc-silicate, with quartz
zoisite (FKM-1):
zoisite (“tanzanite”; 1.00 M3Al apfu) in high grade calc-silicate, with grossular garnet, quartz and calcite
zoisite (FKM-68):
Cr-bearing zoisite (0.01 Cr apfu in high grade meta-gabbroid, with pargasite amphibole and corundum
zoisite (FKM-290):
Cr-bearing zoisite (0.02 Cr apfu in high grade meta-gabbroid
shuiskite-(Mg) (FKM-316):
zoned shuiskite-(Mg) (est. 0.31 XCr apfu & 0.62 YCr apfu) to Cr-bearing (est. 0.35 XCr apfu & 1.04 YCr apfu) pumpellyite-(Mg) in altered chromatite, with zoned uvarovite/Cr-bearing grossular garnet
vesuvianite (FKM-110):
anomalously biaxial vesuvianite in high grade calc-silicate skarn, with fine-grained undifferentiated alteration minerals
vesuvianite (FKM-263):
vesuvianite in Al-rich “calc-skarnoid”, with hibonite and calcite
manganvesuvianite (FKM-334):
Cu-bearing manganvesuvianite in Mn-metasomatite, with opaque hausmannite; (note: colorless portion of sample is epoxy)
ganomalite (FKM-334):
anomalously B(+) ganomalite in high grade calcareous Mn-metasomatite, with phlogopite, calcite and garnet(?)
yoshimuraite (FKM-299):
yoshimuraite in meta-Mn-metasomatite, with rhodonite, hjalmarite amphibole, and quartz
benitoite (FKM-244):
benitoite in serpentine-hosted natrolite veins, with neptunite and natrolite(?)
beryl (FKM-288):
beryl in granite pegmatite-associated Be-F metasomatite, with phenakite, fluorite and biotite
cordierite (FKM-23):
uncommonly B(+) & weakly pleochroic cordierite (1.67 Mg apfu) in granulite facies metapelite, with garnet and rutile
cordierite (FKM-46):
uncommonly B(+) cordierite partially altered to pinite in granulite facies B-bearing metapelite, with garnet and K-feldspar
dravite (FKM-292):
dravite (2.58 YMg apfu) in tourmaline-bearing mica schist, with muscovite dioctahedral mica
foitite (FKM-70):
foitite tourmaline in a B-bearing meta-“advanced argillic” metasomatite, with dumortierite and illite?
uvite (FKM-119):
uvite (OH-dominant) tourmaline (anomalously biaxial) in Mg-metasomatic talc schist, with talc
uvite (FKM-210):
uvite tourmaline in Mg-metasomatite, with magnesite
oxy-schorl (FKM-85):
zoned oxy-schorl tourmaline in granite, with quartz
(FKM-281): oxy-schorl with thin near-rim “oxy-olenite” tourmaline in granite, with quartz and orthoclase “perthite” feldspar
oxy-dravite (FKM-102):
zoned oxy-dravite (core) to dravite (rim) tourmaline in muscovite biotite mica schist
oxy-dravite (FKM-166):
Cr-bearing (0.57 to 0.94 Cr apfu) green oxy-dravite tourmaline in metasomatic fuchsite schist, with quartz and Cr-bearing muscovite dioctahedral mica
(FKM-276): bright green oxy-chromium-dravite (4.68 to 5.18 [Y+Z]Cr apfu; [Y+Z]Cr/[Y+Z](Cr+Al) = 0.72 to 0.79) tourmaline in granulite facies metasomatic calcareous meta-evaporite, with quartz and Cr-bearing tremolite amphibole (100X)
povondraite (FKM-71):
zoned povondraite to “K-povondraite” tourmaline in meta-evaporite, with alkali feldspar and hydromagnesite?
osumilite (FKM-240):
anomalously biaxial osumilite (0.95 Fe2+ apfu; 0.85 Mg apfu) in rhyodacite(?), with tridymite and/or cristobalite
anomalously biaxial with a mod-low 2V°, but the optic sign was inconclusive & the figure was of too low quality to be useful here
aluminosugilite (FKM-173):
pale lilac aluminosugilite cores (1.10 MAl apfu; 0.57 MMn3+ apfu) rimmed by deeper lilac sugilite (1.11 MFe3+ apfu; 0.72 MMn3+ apfu) in Mn-metasomatite, with quartz, pectolite and fine-grained intergrown amphibole+aegirine.
presumably U(-), but the birefringence was too low to obtain a figure
eudialyte (FKM-77):
zoned eudialyte in kakortokite, with albite plagioclase
eudialyte (FKM-130):
eudialyte in nepheline syenite, with aegirine clinopyroxene and alkali feldspar
eudialyte (FKM-145):
eudialyte in agpaitic nepheline syenite, with amphibole, alkali feldspar and nepheline
ferrokentbrooksite (FKM-207):
weakly pleochroic and anomalously slightly biaxial irregularly-zoned ferrokentbrooksite to eudialyte (M2Fe2+ > M2Mn2+; 0.76 to 0.17 M3Nb apfu) in agpaitic nepheline syenite, with albite and nepheline
titantaramellite (FKM-53b):
titantaramellite in Ba-metasomatite, with quartz, gillespite, actinolite and alforsite
cerchiaraite-(Fe) (FKM-53b):
strongly pleochroic zoned cerchiaraite-(Fe) to near cerchiaraite-(Al) in Ba-metasomatite, with sanbornite, gillespite, actinolite and quartz

non-silicates in thin section

nesosilicates 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