Quartz Crystal (specifically Rock Crystal)
Silicon Dioxide (SiO2)
Category
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Quartz Crystal (specifically Rock Crystal)
Silicon Dioxide (SiO2)
Carnelian (Chalcedony)
Silicon Dioxide (SiO2) with Iron Oxide impurities
Conglomerate
Conglomerate
Chert (Nodule)
Chert (Silicon Dioxide, SiO2)
Chert (often called Flint or Chalcedony Jasper)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Biggs Jasper
Cryptocrystalline Quartz (Silicon Dioxide) - SiO2
White Chalcedony (Agate)
Silicon Dioxide (SiO2)
Ironstone (likely Limonite or Goethite nodule)
Hydrothermally altered Ferric Hydroxide (FeO(OH)·nH2O)
Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
Basalt
Basalt (Mafic Extrusive)
Vesicular Basalt
Extrusive mafic igneous rock
Fossiliferous Limestone
CaCO3 (principally Calcite or Aragonite)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Yellow Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Chert (Black Chert/Flint)
Silicon Dioxide (SiO2)
Gold (Elemental Metal)
Gold (Au)
Garnet Schist
Almandine Garnet Schist
Quartzite (specifically Milky Quartz variety)
Quartz (SiO2)
Amethyst
Amethyst (Silicon Dioxide, SiO2 + Fe)
Celestite
Celestine (Strontium Sulfate, SrSO4)
Yellow Calcite
Calcium Carbonate (CaCO3)
Orange Calcite (Carved as a Horned Skull)
Calcium Carbonate (CaCO3)
Yellow Quartz (Citrine Quartz or Yellow Chalcedony)
Silicon Dioxide (SiO2)
Honey Calcite
Calcium Carbonate (CaCO3)
Orange Calcite
Calcium Carbonate (CaCO3)
Orange Calcite
Calcium Carbonate (CaCO3)
Iron Slag
Anthropogenic Iron Silicate
Shale
Shale (Lutite)
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
Specular Hematite Geode/Nodule
Specularite (Polycrystalline Hematite), Fe2O3
Milky Quartz Pebble
Quartz (Silicon Dioxide - SiO2)
Brown Jasper
Jasper (a cryptocrystalline variety of Quartz, SiO2)
Basalt Cobble
Vesicular Basalt (Mafic Extrusive)
Greisen
Greisen
Limestone (specifically Bituminous or Carbonaceous Limestone)
Calcium Carbonate (CaCO3) with Organic Impurities
Green Calcite
Calcium Carbonate (CaCO3)
Epidote (Unakite variety)
Epidosite (Metasomatic rock containing Ca2(Al,Fe)3(SiO4)3(OH))
Green Sandstone
Glauconitic Sandstone
Botryoidal Chalcedony (likely Desert Rose/Agatized Geode Crust)
Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (and associated Flint)
Silicon Dioxide (SiO2)