Metamorphic (Likely Gneiss Or Schist Based On Texture)

Mica-rich schist (likely biotite schist)

Biotite–quartz schist; composition chiefly quartz (SiO₂), biotite mica, and feldspar

Dark weathered metamorphic rock, likely schist or phyllite

Undetermined; probably mica-rich quartz–feldspar schist/phyllite

Ruby (Corundum)

Aluminum oxide (Al2O3) with Chromium traces

Kyanite (Blue Kyanite)

Kyanite (Al2SiO5)

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Kyanite in Quartz

Kyanite (Al2SiO5) with Quartz (SiO2) matrix

Mica-rich pegmatite, likely muscovite schist or granite

Muscovite-dominant quartz–feldspar rock; approximate mica formula KAl₂(AlSi₃O₁₀)(OH)₂

Quartz-rich granitic rock (likely weathered granite)

Granite; chiefly quartz, feldspar, and mica, with possible iron-oxide staining

Schist

Schist (variety likely Mica Schist)

White Sapphire

Corundum (Al2O3)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Biotite-rich schist (likely mica schist)

Mica schist; chiefly quartz (SiO₂), biotite [K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂], feldspar, and minor sulfides/iron oxides

Ruby (Raw Corundum)

Corundum (Al2O3) with Chromium traces

Gneiss

High-grade regional metamorphic rock (Foliated)

Biotite Schist

Schist (Biotite-dominated)

Mica Schist

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

Gneiss

Granitic Gneiss

Probable gneiss

Banding-scale metamorphic rock composed mainly of quartz, feldspar, and mica; possibly granitic gneiss

Milky Quartz with Chlorite Schist Inclusions

Quartz (SiO2) with Chlorite Group silicates (typically (Mg,Fe)3(Si,Al)4O10(OH)2)

Dark gray metamorphic rock fragment

Likely slate or fine-grained schist; mineral composition cannot be confirmed from the image

Biotite-rich granite or granitic gneiss

Coarse-grained quartz–feldspar–biotite rock; likely granite, possibly weakly foliated gneiss

Banded gneiss

Foliated quartz–feldspar gneiss, likely biotite-bearing

Kyanite (Blue or Blue-Grey)

Kyanite (Al2SiO5)

Felsic gneiss, likely granitic gneiss

Quartz–feldspar–mica gneiss; commonly quartz + plagioclase/K-feldspar + biotite or hornblende

Weathered mica schist (tentative)

Mica schist, likely muscovite–biotite schist with quartz and feldspar

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2

Milky quartz-bearing rock, possibly quartzite

Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)

Mica schist, likely biotite–muscovite schist

Mica schist; predominantly quartz, feldspar, biotite and/or muscovite mica. Exact mineral composition cannot be confirmed from the photograph alone.

Schist

Schist (various mineralogical compositions including mica, chlorite, talc, etc.)

Almandine Garnet

Almandine, Fe3Al2(SiO4)3

Granite-like granitic rock

Crystalline plutonic rock, primarily quartz, feldspar, and mica/amphibole

Mica Schist with Quartz and Muscovite

Muscovite-Quartz Schist

Quartz with Schist Inclusion

Crystalline Silicon Dioxide (SiO2) with Muscovite/Biotite Schist

Gneiss

Gneiss (quartz-feldspar-biotite gneiss)

Mica Schist

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

Mica Schist

Mica Schist (primarily Muscovite and Quartz)

Slate

Slate; predominantly fine-grained phyllosilicates (muscovite/illite, chlorite) with quartz and feldspar

Rough Sapphire

Corundum (Al2O3)

Mica Schist

Schist (muscovite/biotite rich regional metamorphic rock)

Likely mica-rich schist

Mica schist, composed mainly of muscovite and/or biotite with quartz and feldspar