Anthracite Coal
Anthracite (Carbon-based sedimentary rock typically classified as metamorphic)
Category
Browse sedimentary (base), then artificial specimens identified by the Rock Identifier community.
Anthracite Coal
Anthracite (Carbon-based sedimentary rock typically classified as metamorphic)
Chert (Brown Variety)
Microcrystalline Quartz (SiO2)
Sandstone (likely Graywacke or Lithic Sandstone)
Arenite / Wacke (SiO2 based with lithic fragments)
Sandstone (Grooved/Weathered)
Arenite (composed primarily of Quartz and Lithic fragments)
Limestone
CaCO3 (principally composed of Calcite)
Ferruginous Conglomerate (or Iron-Rich Concrete/Slag)
Clastic Sedimentary (Silicon Dioxide/Iron Oxide matrix)
Banded Iron Formation (BIF)
Magnetite-Hematite Chert (Banded Iron Formation)
Quartz on Schist
Silicon Dioxide (SiO2) on Foliated Metamorphic Rock
Muscovite Schist
Muscovite Mica Schist (KAl2(AlSi3O10)(OH)2)
Biotite (Mica)
Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)
Hematite
Hematite (Fe2O3)
Mica Schist
Mica Schist (primarily Muscovite and Quartz)
Muscovite Schist
Muscovite (KAl2(AlSi3O10)(OH)2) in Schist
Sandstone with Magnetite and Iron Staining
Clastic Sedimentary Rock (contains Fe3O4 and Limonite/Hematite)
Conglomerate (Asphaltic/Anthropogenic)
Clastic sedimentary rock / Bituminous mixture
Selenite
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Biotite Schist
Biotite Schist
Chert (Flint)
Chert (SiO2)
Mica-rich Sandstone or Micaceous Schist Weathering
Micaceous Schist (Muscovite-Quartz composition)
Ferruginous Conglomerate
Ferruginous Conglomerate (Clastic Sedimentary Rock)
Banded Calcite (often sold as 'Mexican Onyx' or 'Calcite Onyx')
Calcite (Calcium Carbonate, CaCO3)
Jasper and Yellow Chert (Tumbled)
Microcrystalline Quartz (SiO2)
Sandstone
Arenite (SiO2 based with various mineral cements)
Sandstone
Arenite (SiO2 based with various mineral cements)
Native Gold (in earring form)
Gold (Au)
Conglomerate
Conglomerate (clastic sedimentary rock)
River Rocks (Polished River Pebbles)
Stream-rounded clastic sediments
Mica Schist
Mica Schist (primarily Muscovite and/or Biotite composition)
Mica Schist with Iron Staining
Mica Schist
Gneiss
Gneiss (High-grade metamorphic rock)
Travertine
Terrestrial Sedimentary Rock (CaCO3)
Coquina
Biogenic Limestone (Coquina)
Conglomerate
Conglomerate (Sedimentary rock containing rounded clasts)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Gneiss (with Quartz and Biotite Mica)
Gneiss
Marble
Metamorphosed Limestone (main mineral: Calcite, CaCO3)
Sandstone (likely Ferruginous)
Arenite (SiO2 based with Fe2O3/FeO(OH) cement)
Conglomerate
Clastic sedimentary rock (Polymictic Conglomerate)
Schist with Quartz
Mica Schist (contains Muscovite/Biotite and Quartz SiO2)
Bauxite
Alumina-rich rock (consisting of Gibbsite, Boehmite, and Diaspore)
Mica Schist
Mica Schist (primarily Muscovite or Biotite)
Chert (and/or Flint)
Chert (Cryptocrystalline variety of Quartz, SiO2)