Chalcedony (Common Opal or Agate variant)
Silicon Dioxide (SiO₂)
Category
Browse sedimentary like (industrial composite) specimens identified by the Rock Identifier community.
Chalcedony (Common Opal or Agate variant)
Silicon Dioxide (SiO₂)
Muscovite Mica Schist
Metamorphic rock rich in muscovite mica (KAl2(AlSi3O10)(F,OH)2)
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
Bauxite
Aluminum ore (mixture of gibbsite Al(OH)3, boehmite γ-AlO(OH), and diaspore α-AlO(OH))
Chert Nodule (Flint)
Microcrystalline Quartz (SiO2)
Green Glass Slag
Amorphous Silicon Dioxide (SiO2) with metal oxide impurities
Yellow Calcite
Calcium Carbonate (CaCO3)
Sandstone
Arenite (SiO2 + various cementing minerals)
Basalt
Basalt
Garnet Schist
Almandine Garnet in Mica Schist
Satin Spar (often sold as Selenite)
Gypsum (CaSO4·2H2O)
Bituminous Coal
Bituminous coal (Carbonaceous sedimentary rock)
Agate (Chert/Chalcedony)
Silicon Dioxide (SiO2)
Garnet Schist
Garnetiferous Mica Schist
Quartz / Agate Nodule
Silicon Dioxide (SiO2)
Anthracite Coal
Anthracite
Conglomerate
Clastic Sedimentary Rock (Conglomerate)
Green Calcite
Calcium Carbonate (CaCO3)
Sandstone
Arenite (specifically Quartz Arenite)
Sandstone with Foliose Lichen
Arenite (Rock matrix) with Xanthoparmelia or Flavoparmelia (Lichen genus)
River Stone (Limestone)
Sedimentary Calcium Carbonate (CaCO3)
Ironstone (Limonitic/Hematitic Sandstone)
Ferruginous sandstone (predominantly Fe2O3 and FeO(OH))
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 predominantly)
Red Sandstone
Arenite (SiO2 with Fe2O3)
Anthracite Coal
Anthracite (Metamorphosed Coal)
Chert (Quartz Variety)
Microcrystalline Silicon Dioxide (SiO2)
Red Sandstone
Arenite (Ferruginous Sandstone)
Orange Calcite
Calcium Carbonate (CaCO3)
Sandstone with Iron Staining
Arenite (SiO2 with FeO(OH) impurities)
Bauxite
Bauxite (mixture including Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Glauconitic Sandstone
Glauconitic Quartz Arenite (with K,Mg,Fe,Al silicate hydroxide)
Garnet (likely Almandine)
Almandine (Fe3Al2(SiO4)3)
Chert (Flint)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Garnet (Polished)
Nesosilicate (Group formula: X3Y2(SiO4)3)
Mica Schist (with Muscovite)
Muscovite/Quartz Schist (KAl2(AlSi3O10)(OH)2)
Red Sandstone
Arenite (typically with iron oxide/hematite cement)
Sandstone
Arenite
Sandstone
Arenite (SiO2 primarily)
Milky Quartz Nodule / Geode precursor
Silicon Dioxide (SiO2)
Garnet in Host Rock
Garnet Group (A3B2(SiO4)3)
Sandstone
Arenite (SiO2 primarily)