Feldspar (specifically Orthoclase)
Potassium Aluminum Silicate (KAlSi3O8)
Category
Browse metamorphic and igneous specimens identified by the Rock Identifier community.
Feldspar (specifically Orthoclase)
Potassium Aluminum Silicate (KAlSi3O8)
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
Natural freshwater pearls
Pearl (nacreous calcium carbonate; chiefly aragonite, CaCO₃)
Biotite Schist
Biotite Gneissic Schist (K(Mg,Fe)3AlSi3O10(OH)2)
Gneiss and Igneous Rock Collection
Foliated Metamorphic Rock (Gneiss) / Igneous Rocks
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
Mica (Lepidolite or Muscovite)
Phyllosilicate mineral (KAl2(AlSi3O10)(OH)2 for Muscovite)
Garnet (Almandine)
Almandine (Fe3Al2(SiO4)3)
Biotite (Mica)
Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)
Peacock Ore
Bornite (Cu5FeS4)
Epidote in Quartz (Epidosite)
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Magnetite with Quartz
Magnetite (Fe3O4)
Lapis Lazuli
Lapis Lazuli (Rock containing Lazurite, Calcite, and Pyrite)
Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
Gneiss
Metamorphic Gneiss
Diopside (likely Chromian Diopside)
Diopside, part of Clinopyroxene family of inosilicates. Chemical formula: CaMgSi2O6. The green variety is often Chromian Diopside due to chromium impurities.
Banded gneiss (likely garnet-biotite or quartz-feldspar gneiss)
Gneiss; predominantly quartz (SiO₂), feldspar, and dark biotite/amphibole
Red corundum (ruby-colored polished crystal)
Corundum, aluminum oxide (Al₂O₃); red color is typically caused by chromium
Schist
Metamorphic Rock (Schist)
Banded Gneiss
Gneiss (Metamorphic Rock)
White tumbled stone, likely quartz or calcite
Indeterminate; possibly quartz (SiO₂) or calcite (CaCO₃)
Epidote
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Milky Quartz
Quartz / Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
Epidote
Calcium aluminum iron silicate hydroxide (Ca2(Al,Fe)3(SiO4)3(OH))
Granite-like granitic rock
Crystalline plutonic rock, primarily quartz, feldspar, and mica/amphibole
Foliated Gneiss
Gneiss (Metamorphic Rock)
Gneiss
Foliated Metamorphic Gneiss
Gneiss
Gneissic Metamorphic Rock
Quartzite River Pebble
Metamorphic Quartzite (SiO2)
Weathered quartz-rich cobble, possibly quartzite or feldspar-rich granite
Quartz–feldspar aggregate; identification is uncertain from the photograph
Quartz
SiO2
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Quartz crystals on matrix
Silicon dioxide (SiO2)
White Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Pyrite
Iron sulfide (FeS2)
Quartz Pebble
Silicon Dioxide (SiO2)
White Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)