Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Category
Browse metamorphic or igneous alteration specimens identified by the Rock Identifier community.
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Milky Quartz
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Ruby
Corundum (Al2O3 with Chromium traces)
Schist
Schist (various mineral compositions)
Marble
Marbles are primarily composed of calcite (calcium carbonate, CaCO3) or dolomite (calcium magnesium carbonate, CaMg(CO3)2).
Giallo Ornamental Granite
Phaneritic Igneous Rock (composed of Quartz, Feldspar, and Mica)
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Iron Oxide inclusions (Fe2O3)
Quartz (River Stone)
Silicon Dioxide (SiO2)
Quartz (Iron-Stained Quartz Pebble)
Silicon Dioxide (SiO2)
Schist
Schist (various compositions)
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Amethyst
Quartz (Silicon Dioxide with Iron impurities), SiO2
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Gneiss
Gneiss
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Granitic Pegmatite
Granitic Pegmatite with Quartz and Feldspar
Gneiss with Quartz Veining
Gneiss (High-grade regional metamorphic rock)
Muscovite Mica
Muscovite - KAl2(AlSi3O10)(OH)2
Mica (Muscovite)
Muscovite, KAl2(AlSi3O10)(OH)2
Greenstone (Greenstone River Pebble)
Greenschist (metamorphosed mafic igneous rock)
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(OH)₄(BO₃)₃Si₆O₁₈)
Labradorite (tumbled)
Labradorite (a plagioclase feldspar mineral between anorthite and albite; chemical formula: (Ca,Na)(Si,Al)4O8)
Aquamarine
Beryl (Be3Al2Si6O18), specifically the blue-green variety
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Quartz
Quartz (SiO₂)
Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz with Country Rock contact
Silicon Dioxide (SiO2) in contact with Metamorphic/Igneous rock
Gneiss (specifically a Banded Gneiss pebble)
Gneiss (High-grade Regional Metamorphic Rock)
Baroque Pearl (and potentially a small Sapphire/Blue Topaz)
Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.
Green Aventurine and Clear Quartz
Green Aventurine (Silicon Dioxide - SiO2 with Fuchsite inclusions); Clear Quartz (Silicon Dioxide - SiO2)
Rough Garnet (likely Almandine or Pyrope)
Garnet group; Almandine Fe3Al2(SiO4)3 or Pyrope Mg3Al2(SiO4)3
Amethyst
Silicon Dioxide with Iron impurities (SiO2)
Citrine
Silicon Dioxide (SiO2)
Smoky Quartz (with Hematite inclusions)
Silicon Dioxide (SiO2)
Pyrite
Iron Disulfide (FeS2)
Milky Quartz with Iron Inclusions
Quartz (Silicon Dioxide, SiO2)
Orthoclase Feldspar (Salmon variety)
Orthoclase, KAlSi3O8
Milky Quartz
Quartz (Silicon Dioxide - SiO2)