Metamorphic (Likely Gneiss Or Schist Based On Texture)

Banded Gneiss

Gneiss

Gray foliated metamorphic rock, likely gneiss or schist

Quartz–feldspar–mica metamorphic rock; exact identification requires a fresh surface and testing

Likely metamorphic schist

Mica schist, probably quartz–biotite schist

Weathered gneiss or schist specimen

Micaceous quartz–feldspar metamorphic rock; exact identification requires testing

Garnet-bearing schist or gneiss

Garnet-mica schist/gneiss; chiefly quartz, feldspar, mica, and almandine–pyrope garnet

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Likely weathered gneiss

Banded quartz–feldspar–mica gneiss

Biotite / Black Mica

K(Mg,Fe)3(AlSi3O10)(F,OH)2

Gneiss

Gneiss (High-grade metamorphic rock)

Foliated metamorphic rock, likely mica schist

Muscovite–biotite schist with quartz and feldspar

Banded metamorphic rock, likely gneiss

Banded quartzofeldspathic gneiss (probable paragneiss or orthogneiss)

Muscovite Mica

KAl2(AlSi3O10)(F,OH)2

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(F,OH)2

Mica (Lepidolite or Muscovite)

Phyllosilicate mineral (KAl2(AlSi3O10)(OH)2 for Muscovite)

Gneiss (specifically a Hornblende Gneiss or Micaceous Gneiss)

Gneiss (metamorphic rock composed primarily of quartz, feldspar, and mafic minerals)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(F,OH)2)

Iridescent schist or phyllite

Micaceous quartz-rich schist/phyllite, likely containing muscovite or chlorite

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Biotite-bearing gneiss or schist

Quartz–feldspar–mica metamorphic rock, likely mica schist/gneiss

Quartzite

Quartzite (SiO2)

Biotite Schist

Biotite-rich Schist

Schist

Mica Schist (Metamorphic rock)

Dark metamorphic rock, likely biotite schist or gneiss

Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing

Gneiss

Quartz–feldspar–mica gneiss

Schist

Mica Schist (contains muscovite/biotite and quartz)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide), KAl2(AlSi3O10)(OH)2

Likely biotite-rich metamorphic rock (mica schist or amphibolite)

Mica schist/amphibolite; chiefly biotite mica ± hornblende, plagioclase, quartz

Fuchsite

Chromium-rich Muscovite (KAl2(AlSi3O10)(OH)2)

Tumbled or naturally etched mica-rich mineral specimen, likely muscovite

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂; possibly phlogopite mica

Schist

Crystalline Metamorphic Schist

Likely biotite-bearing metamorphic rock (schist or gneiss)

Mica schist/gneiss; chiefly quartz, feldspar, and biotite mica

Muscovite

KAl2(AlSi3O10)(OH)2

Muscovite Mica

KAl2(AlSi3O10)(OH)2

Schist (likely Mica Schist)

Mica Schist

Quartz-bearing metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining

Schist or Gneiss pebble

Metamorphic rock (Schist/Gneiss)

Biotite (Mica)

Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)

Foliated metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (provisional identification)

Weathered metallic sulfide-bearing rock, possibly schist or gneiss

Indeterminate; likely mica-rich metamorphic rock with iron sulfides or magnetite

Likely biotite-bearing schist or gneiss

Mica schist/gneiss; chiefly quartz, feldspar, and biotite mica

Schist

Mica Schist

Micaceous schist (likely muscovite–biotite schist)

Mica schist; primarily quartz (SiO₂), feldspar, muscovite and/or biotite micas