Chert (varieties include Flint and Mudstone)
Microcrystalline Silica (SiO2)
Category
Browse man made object (coin) specimens identified by the Rock Identifier community.
Chert (varieties include Flint and Mudstone)
Microcrystalline Silica (SiO2)
Chert (with Desert Varnish/Iron Stain)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2 + Fe2O3)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
Diorite
Diorite
Clear Quartz
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Bauxite
Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))
Sandstone
Arenite (composed primarily of Quartz: SiO2)
Marble
Metamorphic Limestone (CaCO3)
Rough Diamond
Diamond (pure Carbon, C)
Tektite (Indochinite)
Tektite (Amorphous Silica Glass)
Diorite
Diorite (Intermediate intrusive igneous rock)
Natural Pearl (appearing in a jewelry setting)
Calcium Carbonate (mostly Aragonite), CaCO3 with Conchiolin
Sandstone (Quartz Arenite)
Sandstone (dominated by SiO2 quartz grains)
Granite
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)
Sandstone (likely Quartzose Sandstone)
Arenite
Obsidian (Black Obsidian)
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Granite (Pegmatitic)
Phaneritic Felsic Igneous Rock
Ferruginous Sandstone (Ironstone)
Clastic Sedimentary Rock (composed of SiO2 with Fe2O3/FeO(OH) cement)
Turquoise
Hydrated phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O
Lapis Lazuli (in Matrix)
Na8[Al6Si6O24]S2 (Lazurite as the primary component)
Amber
Succinates (Organic Fossilized Resin)
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Grey Chalcedony (Agate)
Silicon Dioxide (SiO2)
Carnelian
Carnelian (a variety of Chalcedony, which is a microcrystalline quartz, SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)
Moonstone
Orthoclase Feldspar (KAlSi3O8) or Albite mixtures
Chert (Flint)
Microcrystalline quartz (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2) with trace aluminum and irradiation
Jasper Marble
Silicon Dioxide (SiO2) with Impurities
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Agate
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Greenschist (Greenstone)
Chlorite schist (primarily Chlorite-Epidote-Actinolite-Albite)
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Yellow Jasper
SiO2 (Silicon Dioxide)
Ocean Jasper
Silicon Dioxide (SiO2)
Granite
Granite (Felsic Plutonic Rock)