Biotite (Black Mica)
Biotite (K(Mg,Fe)3AlSi3O10(OH)2)
Category
Browse sedimentary or metamorphic derived specimens identified by the Rock Identifier community.
Biotite (Black Mica)
Biotite (K(Mg,Fe)3AlSi3O10(OH)2)
Arsenopyrite with Schist Matrix
Arsenopyrite (FeAsS)
Greenstone / Diabase Porphyry
Porphyritic Diabase (Micro-gabbro)
Quartz (Milky/Smoky variety on matrix)
Silicon Dioxide (SiO2)
Anthracite Coal
Anthracite (Carbon Content: 86%–98%)
Gneiss (with Quartz and Biotite Mica)
Gneiss
Gneiss
Gneiss (High-grade Metamorphic Rock)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Schist (specifically Mica Schist)
Mica Schist (primarily composed of Muscovite KAl2(AlSi3O10)(OH)2 and Biotite)
Gneiss
Gneiss
Mica Schist
Mica Schist
Gneiss
Gneissic Metamorphic Rock (Mineral composition: Quartz, Feldspar, Amphibole/Biotite)
Biotite Schist
Biotite Schist
Quartzite with Chert inclusions
Metamorphosed Quartz-rich Rock (SiO2)
Orange Calcite (Cleavage Rhomb)
Calcite (Calcium Carbonate, CaCO3)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Amphibolite (specifically Hornblende Schist/Gneiss)
Amphibole-rich Metamorphic Rock
Pyrite
Iron Sulfide (FeS2)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) within Sedimentary/Metamorphic Matrix
Greenschist
Chlorite schist
Phyllite
Phyllite
Gneiss (with Quartzite and Biotite)
Gneiss containing SiO2 (Quartz), K(Mg,Fe)3AlSi3O10(OH)2 (Biotite), and (K,Na,Ca)AlSi3O8 (Feldspar)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Schist (Micaceous Schist)
Schist (comprising Muscovite/Biotite mica, Quartz, and Feldspar)
Gneiss
Gneiss
Smoky Quartz and Biotite Schist
Quartz-Biotite Schist (SiO2 + K(Mg,Fe)3AlSi3O10(F,OH)2)
Quartzite
Quartzite (SiO2)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Marble
Recrystallized Calcite (CaCO3)
River Cobble (Phyllite or Quartzite)
Metasedimentary Rock (often containing SiO2 or KAl2(AlSi3O10)(OH)2)
Slate
Foliated Metamorphic Rock (composed primarily of Quartz, Muscovite, and Illite)
Schist
Mica Schist
Gneiss
Gneiss
Banded Gneiss (with Quartz Vein)
Gneiss (Metamorphic rock of varying mineralogy)
Gneiss (specifically a Granitic Gneiss specimen)
Gneiss (high-grade metamorphic rock primarily composed of Quartz, Feldspar, and Biotite/Amphibole)
Red aventurine
Silicon Dioxide (SiO2) with Hematite/Goethite inclusions
Gneiss
Gneiss (High-grade Metamorphic Rock)
Quartz Vein with Host Rock (Greywacke/Siltstone)
Silicon Dioxide (SiO2) within Clastic Sedimentary/Metamorphic Matrix
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)
General Gravel (River Rock/River Stones)
Mixed Lithic Sediments (Conglomerate Clasts)
Quartz (likely) / Siliceous rock with quartz phenocrysts (if a rock fragment)
Quartz (SiO₂)
Quartz
Quartz (Silicon Dioxide - SiO2)