Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
Category
Browse antropogenic (man made material) specimens identified by the Rock Identifier community.
Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
Chert (and/or Flint)
Chert (Cryptocrystalline variety of Quartz, SiO2)
Chert (and associated river cobbles)
Silicon dioxide (SiO2)
Granite
Granite (Felsic Plutonic Rock)
Sandstone (likely Fossilized Wood or Concrete Simulacrum)
Arenite / Silicified Wood / Anthropogenic Concrete
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
Chert (often called Flint or Agate nodule)
Cryptocrystalline Quartz (SiO2)
Man-made Green Quartz (Lab-grown or Treated)
Silicon Dioxide (SiO2) with artificial coloration
Goldstone (blue-goldstone–style glass) beads
Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral
Jasper
Silicon Dioxide (SiO2)
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (often called Flint)
Chert (SiO2)
Diamond
Carbon (C)
Sandstone
Arenite
Green Slag Glass
Cullet (Amorphous Silicon Dioxide with impurities)
Graphite
Graphite (Carbon, C)
Sandstone
Arenite
Synthetic Faux Fur Fursuit
Polyacrylonitrile / Polyester (Synthetic Textile)
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Chert (Arrowhead Shard)
Microcrystalline silica (SiO2)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
Chipped Glass/Plastic Fragment
Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Fossilized oyster shell
Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
Industrial Slag
Anthropogenic Vitreous Slag
Chert / Green Jasper
Silicon Dioxide (SiO2)
Diorite (River Pebble)
Intermediate Phaneritic Igneous Rock
White Marble
Recrystallized Calcite Rock (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Likely weathered iron-rich rock or slag fragment
Uncertain; possibly limonite/goethite-rich material (FeO(OH)·nH₂O)
Diamond (Faceted)
Carbon (C)
Blue glass-like tumbled specimen
Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image
Tumbled greenstone (likely serpentinite or green jasper)
Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Coquina
Bioclastic Limestone (Calcium Carbonate, CaCO3)
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
Iron Slag
Ferrous slag (primarily silicates and oxides of calcium, iron, and magnesium)
Flint (or Chert with cortex)
Silicon dioxide (SiO2)
Chert (varieties include Flint and Mudstone)
Microcrystalline Silica (SiO2)