Basalt
Basalt (Mafic Extrusive Igneous Rock)
Category
Browse industrial byproduct (often confused with igneous rocks or meteorites) specimens identified by the Rock Identifier community.
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Pyrite
Iron Sulfide (FeS2)
Chalcedony (Agate/Chert variety)
Silicon Dioxide (SiO2)
Chalcedony (Agate/Chert variety)
Silicon Dioxide (SiO2)
Pyrite in Matrix (Fool's Gold)
Iron Disulfide (FeS2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Iron Oxide inclusions (Fe2O3)
Likely anthracite coal
Anthracite; predominantly carbon (C), with minor mineral impurities
Basalt with Magnetite
Crystalline Basalt (Primarily Plagioclase and Pyroxene) with Magnetite (Fe3O4)
Quartz (Milky/Yellowish)
Silicon Dioxide (SiO2)
Fluorite
Calcium fluoride (CaF2)
Fluorite
Calcium Fluoride (CaF2)
Ruby
Corundum (Al2O3 with Chromium traces)
Blue Topaz
Al2SiO4(F,OH)2
Quartzite with Quartz Vein
Metamorphosed sandstone (SiO2)
Chert (Red Jasper)
Microcrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
Quartzite River Rock
Metamorphic Quartzite (primarily SiO2)
Agate
Silicon Dioxide (SiO2) - Banded Chalcedony
Graphite Schist
C (Carbonaceous Schist)
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
Limestone
Sedimentary rock composed primarily of Calcite (CaCO3)
Garnet (likely Almandine)
Almandine - Fe3Al2(SiO4)3
Blue Topaz (facetted in jewelry)
Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)
Agate
Silicon Dioxide (Chalcedony), SiO2
Gneiss
Metamorphic Gneiss (High-grade regional metamorphism)
Polished fluorite sphere
Fluorite (calcium fluoride, CaF₂)
Common Opal
Hydrated amorphous silica (SiO2·nH2O)
Howlite (tumbled stone)
Howlite, Ca₂B₅SiO₉(OH)₅
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Quartzite
Quartzite (SiO2)
Milky Quartz (Crystal Cluster)
Silicon Dioxide (SiO2) - Quartz Variety
Schorl (Black Tourmaline) in Pegmatite
Sodium Iron Aluminum Borosilicate (NaFe3Al6(BO3)3Si6O18(OH)4)
Sodalite
Na8(Al6Si6O24)Cl2
Ironstone
Ferruginous Sedimentary Rock (composed of Goethite, Hematite, and Limonite)
Pyrite
Iron Sulfide (FeS2)
Ironstone (likely Limonite or Goethite)
Ferruginous sedimentary rock (FeO(OH)·nH2O)
Quartzite
Quartzite (primarily SiO2)
Limestone
Calcium Carbonate (CaCO3)
Pyrite Nodules / Weathered Pyrite
Iron Sulfide (FeS2)