Quartz Crystal
Silicon Dioxide (SiO2)
mineral
Category
Metamorphic (Pseudo Igneous)
Browse metamorphic (pseudo igneous) specimens identified by the Rock Identifier community.
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Quartz (Pink/Rose Quartz or Quartz Crystal)
Silicon Dioxide (SiO2)
mineral
Black Tourmaline
Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)
mineral
White Quartz
Silicon Dioxide (SiO2)
mineral
Iceland Spar (Optical Calcite)
Calcite (CaCO3)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Black Tourmaline
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
mineral
Quartz with Mica/Host Rock
Silicon Dioxide (SiO2) with Phyllosilicates
mineral
Pyrite in Matrix (Gold-colored Chalcopyrite or Pyrite)
Iron Sulfide (FeS2) / Copper Iron Sulfide (CuFeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Quartz (Milky/Crystalline fragment)
Silicon Dioxide (SiO2)
mineral
Citrine
Silicon Dioxide (SiO2)
mineral
Amethyst
SiO2 (Silicon Dioxide with Iron impurities)
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Likely polished/tumbled dark mineral or glassy rock fragment
Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Tiny amber-colored crystal fragment
Indeterminate; possibly quartz, feldspar, mica, or a sulfide mineral
mineral
Milky Quartz Pebble
Crystalline Silicon Dioxide (SiO2)
mineral
Milky Quartz in Matrix
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Rough Citrine Quartz
Citrine (Silicon Dioxide, SiO2 with iron impurities)
mineral
Almandine Garnet
Almandine, Fe3Al2(SiO4)3
mineral
Muscovite
KAl2(AlSi3O10)(OH)2
mineral
Almandine Garnet
Almandine, Fe3Al2(SiO4)3
mineral
Biotite / Black Mica
K(Mg,Fe)3(AlSi3O10)(F,OH)2
mineral
Muscovite Mica
Muscovite (Potassium Aluminum Silicate) - KAl2(AlSi3O10)(F,OH)2
mineral
Blue Sapphire (in a faceted jewelry setting)
Corundum (Al2O3) with trace Iron and Titanium
mineral
Schist
Metamorphic rock (Schist)
metamorphic
Migmatite
Migmatite (Mixed metamorphic-igneous rock)
metamorphic
Silicified oyster fossil
Fossil oyster shell, commonly Ostrea or Crassostrea, replaced or encrusted by chalcedony/quartz
fossil
Milky quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Magnetite Sand (Black Sand)
Magnetite (Fe3O4)
mineral
Weathered schist or gneiss fragment
Quartz–feldspar–mica metamorphic rock; likely mica schist or gneiss
metamorphic
Small quartz-rich pebble or rock fragment
Quartz (silicon dioxide, SiO₂), possibly with iron-oxide staining or host-rock inclusions
mineral
Muscovite mica
Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂
mineral
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
Mineral
Osumilite in Granite Matrix
(K,Na)(Fe,Mg)2(Al,Fe)3(Si,Al)12O30
mineral
Plagioclase Feldspar (specifically Albite/Oligoclase)
(Na,Ca)(Si,Al)4O8
mineral
Magnetite-rich ironstone (probable magnetite ore)
Magnetite, Fe₃O₄, likely in a fine-grained ironstone matrix
mineral
Weathered granite or granitic gneiss
Granite; mainly quartz (SiO₂), feldspar, and mica; possible weak gneissic texture
igneous