Metamorphic (Likely Gneiss Or Schist Based On Texture)

Quartz-rich metamorphic fragment (likely mica schist)

Mica schist, probably muscovite–quartz schist

Biotite-rich schist (likely mica schist)

Mica schist; predominantly quartz, biotite mica, and feldspar

Garnet (likely Almandine)

Almandine (Fe3Al2(SiO4)3)

Weathered schist or gneiss fragment

Quartz–feldspar–mica metamorphic rock; likely mica schist or gneiss

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

Biotite schist

Mica schist, chiefly quartz–feldspar–biotite

Gneissic boulder

Gneiss, typically quartz–feldspar–mica gneiss

Garnet (Almandine/Pyrope series)

Silicate mineral (Almandine: Fe3Al2Si3O12; Pyrope: Mg3Al2Si3O12)

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Rounded gray metamorphic pebble, likely gneiss or mica schist

Quartz–feldspar–mica metamorphic rock; exact identification requires a close examination or thin section

Biotite schist (probable mica schist)

Mica schist; chiefly quartz, biotite mica, and feldspar

Gneiss (likely biotite–quartz–feldspar gneiss)

Foliated gneiss; chiefly quartz (SiO₂), feldspar, biotite, and possibly amphibole

Painted River Rock (likely Quartzite or Granite)

Quartzite or Granitic Gneiss (painted)

Muscovite Mica

Muscovite: KAl2(AlSi3O10)(OH)2

Muscovite Mica

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

Muscovite mica

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

Gneiss (specifically a granitic gneiss cobble)

Gneiss (high-grade regional metamorphic rock)

Sapphire

Corundum (Al2O3)

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

River Pebble (Gneiss/Schist mix)

Metamorphic rock aggregate

Likely raw mica-bearing mineral fragment

Possibly biotite mica or a biotite-rich metamorphic fragment; identification is limited by the dark, blurred image

Schist

Mica Schist

Biotite Mica in Quartz

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2) in Quartz (SiO2)

Iron-stained garnet-bearing rock, possibly almandine garnet

Garnet-group silicate, likely almandine (Fe₃Al₂Si₃O₁₂), in a quartz–iron-oxide matrix

Micaceous Schist

Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)

Dark foliated metamorphic rock, likely schist

Mica schist, probably muscovite–biotite schist

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Mica-rich metamorphic rock, likely mica schist

Muscovite–biotite schist, possibly with garnet and quartz

Gneiss

Gneiss (High-grade metamorphic rock)

Garnet

Garnet Group (formula varies: e.g., Almandine Fe3Al2Si3O12 or Pyrope Mg3Al2Si3O12)

Biotite Schist

Biotite Gneiss/Schist (approximate formula K(Mg,Fe)3AlSi3O10(OH)2)

Quartz-rich metamorphic rock, likely quartzite

Quartzite (mostly microcrystalline quartz, SiO₂), possibly mica-bearing

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Fuchsite

K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)

Banded gneiss pebble

Gneiss, commonly quartz–feldspar–mica gneiss

Gneiss

Gneiss (High-grade metamorphic rock)

Mica Schist with Iron Staining

Muscovite/Biotite Schist

Pyrite-bearing schist (likely mica schist)

Muscovite–quartz schist with disseminated pyrite (FeS₂)

Likely garnet-bearing schist or gneiss

Mica schist/gneiss containing quartz, feldspar, mica, and possible almandine garnet