Gneiss
Gneiss (Metamorphic Rock)
Category
Browse metamorphic (likely gneiss or schist based on texture) specimens identified by the Rock Identifier community.
Gneiss
Gneiss (Metamorphic Rock)
Serpentinite (likely)
Serpentinite, dominated by serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and relic olivine/pyroxene
Biotite Schist
Biotite-rich Schist (K(Mg,Fe)3AlSi3O10(F,OH)2)
Weathered granite or granitic gneiss cobble
Granite; primarily quartz, feldspar, and mica
Gneissic granite / granitic gneiss
Quartz–feldspar–mica gneiss; composition commonly quartz (SiO₂), feldspars, and biotite/muscovite
Fuchsite
K(Al,Cr)2(AlSi3O10)(OH)2
Dark metamorphic rock, possibly schist
Mica schist (probable; commonly quartz + muscovite/biotite, with possible graphite or chlorite)
Gneiss with Quartz Vein
Metamorphic Gneiss
Mica Schist
Mica Schist (primarily Muscovite or Biotite KAl2(AlSi3O10)(OH)2)
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
Gneiss
Gneiss
Tanzanite
Blue-violet Zoisite (Ca2Al3(SiO4)3(OH))
Garnet
Almandine (Fe3Al2(SiO4)3)
Mica Schist
Mica Schist (primarily Muscovite and Quartz)
River Pebble (Gneiss or Quartzite)
Metamorphic rock specimen (likely Gneiss or impure Quartzite)
Speckled rounded stone, likely granite or granitic gneiss
Granite/granitic gneiss; primarily quartz (SiO₂), feldspar, and dark mica or amphibole
Mica Schist
Mica Schist (KAl2(AlSi3O10)(OH)2 in Matrix)
Tourmaline (likely Schorl)
Tourmaline Group Mineral (e.g., Schorl for black varieties); (Na,Ca)(Li,Mg,Fe,Mn,Al)3Al6(BO3)3Si6O18(OH)4
Quartz Mica Schist
Mica-Quartz Schist (Chemical: SiO2 + KAl2(AlSi3O10)(OH)2)
Banded Gneiss / Metamorphic River Pebble
Gneiss (Foliated Metamorphic Rock)
Graphite-rich schist (likely graphite ore)
Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar
Sandstone (with biological crust)
Arenite (SiO2 based)
Sandstone (Stream-rounded)
Arenite (SiO2 based)
Quartz (likely)
Quartz (SiO2 - Silicon Dioxide)
Fuchsite
K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)
Red Garnet Gemstone
Pyrope-Almandine Garnet (Mg3Al2(SiO4)3 to Fe3Al2(SiO4)3)
Quartzite pebble
Quartzite (SiO2 based)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
Fuchsite
Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)
Biotite Mica
K(Mg,Fe2+)3(Al,Fe3+)Si3O10(OH,F)2
Mica Schist
Mica Schist (Predominantly Muscovite/Biotite)
Blue Star Sapphire
Corundum (Al2O3)
Garnet (specifically Almandine or Pyrope)
Almandine (Fe3Al2Si3O12) or Pyrope (Mg3Al2Si3O12)
Corundum (Ruby/Sapphire crystal)
Al2O3 (Aluminum Oxide)
Schist
Metamorphic Rock (Schist)
Copper-bearing schist (likely bornite/chalcopyrite ore)
Micaceous schist with sulfide minerals, chiefly bornite (Cu₅FeS₄) and/or chalcopyrite (CuFeS₂)
Quartzite with Gneissic Banding
Quartzite (primarily SiO2) with mafic mineral inclusions
Mica Schist
Mica Schist (KAl2(AlSi3O10)(OH)2 / K(Mg,Fe)3AlSi3O10(OH)2)
Gneiss
Gneiss
Gneiss
Gneiss
Blue Topaz
Al2SiO4(F,OH)2
Gneiss
Metamorphic Gneiss