Sandstone
Arenite
Category
Browse man made material (constructed) specimens identified by the Rock Identifier community.
Sandstone
Arenite
Graphite
Graphite (Carbon, C)
Synthetic Faux Fur Fursuit
Polyacrylonitrile / Polyester (Synthetic Textile)
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Eurasite (or Ferruginous Sandstone)
Ferruginous Sandstone (SiO2 with Fe2O3/FeOOH)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
Ferrochrome Slag
Industrial Glassy Slag (Fe-Cr alloy byproduct)
Chipped Glass/Plastic Fragment
Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic
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)
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Petrified Wood
Silicified Wood (SiO2)
Slag
Ferrous Slag (Siliceous industrial waste)
Chert / Green Jasper
Silicon Dioxide (SiO2)
Diorite (River Pebble)
Intermediate Phaneritic Igneous Rock
White Marble
Recrystallized Calcite Rock (CaCO3)
Diamond (Faceted)
Carbon (C)
Likely weathered iron-rich rock or slag fragment
Uncertain; possibly limonite/goethite-rich material (FeO(OH)·nH₂O)
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)
Chert (Arrowhead Shard)
Microcrystalline silica (SiO2)
Coquina
Bioclastic Limestone (Calcium Carbonate, CaCO3)
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
Blue-beaded gemstone jewelry, likely lapis lazuli or dyed blue agate
Uncertain from the image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or blue chalcedony (SiO₂)
Granodiorite
Granodiorite
Flint (or Chert with cortex)
Silicon dioxide (SiO2)
Chert (varieties include Flint and Mudstone)
Microcrystalline Silica (SiO2)
Polished blue-green glassy slag or coated mineral fragment
Most likely man-made colored glass/slag; exact composition cannot be determined visually
Tumbled amber-colored chalcedony or jasper
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper
Banded Sandstone
Arenite with Liesegang banding
Diamond
Carbon (C)
Chert (Chocolate or Brown Flint)
Chert (SiO2)
Quartzite
Silica (SiO2) quartzite
Petrified Wood (Silicified Wood)
Silicified Paleoflora (mainly Quartz, SiO2)
Chert Arrowhead (Lithic Tool)
Microcrystalline quartz (SiO2) - Archeological lithic artifact
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
Diamond (in a jewelry setting)
Diamond (Carbon, C)
Chert (Flint)
Microcrystalline quartz (SiO2)
Diamond
Carbon (C)