Red-orange cabochon, likely carnelian or glass imitation
Carnelian: chalcedony (microcrystalline SiO₂), commonly iron-colored
Category
Browse anthropogenic (man made material mimicking sedimentary rock) specimens identified by the Rock Identifier community.
Red-orange cabochon, likely carnelian or glass imitation
Carnelian: chalcedony (microcrystalline SiO₂), commonly iron-colored
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Sandstone
Arenite (SiO2 primarily)
Chert (Black Flint)
Silicon Dioxide (SiO2)
Sandstone (likely Quartzose Sandstone)
Arenite
Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks
Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock
Blue glass-like bead or gemstone keychain ornament
Indeterminate; likely cobalt-blue glass or synthetic blue spinel, not identifiable as a natural mineral from the image
Sandstone (with iron staining)
Quartz Arenite / Ferruginous Sandstone
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
Iron-stained quartz-rich rock, possibly jasper or chert
Microcrystalline quartz (SiO₂) with iron oxides/hydroxides
Chert (Arrowhead/Projectile Point)
Cryptocrystalline Quartz (SiO2)
White Marble
Recrystallized Calcite Rock (CaCO3)
Hematite
Iron(III) oxide (Fe2O3)
Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')
Calcite (Calcium Carbonate, CaCO3)
Sandstone (specifically Arkose or Quartz Arenite)
Arenite (primarily SiO2 with possible Feldspar)
River Pebbles (Chert and Quartzite)
Sedimentary Clastic Rock (Silica-rich)
Pink Granite
Phaneritic Felsic Igneous Rock (Granite)
Coquina / Fossiliferous Limestone
Calcareous bioclastic sedimentary rock (CaCO3)
Opalite (likely man-made glass)
Opalite; amorphous silica glass, not a natural mineral
Slate
Metamorphic Pelitic Rock
Chert (Flint)
Silicon Dioxide (SiO2)
Crushed Limestone
Calcium Carbonate (CaCO3)
Chert (varietal Chalcedony or Flint)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Likely clear quartz crystal or glass-like gemstone
Quartz, silicon dioxide (SiO₂); exact identification is uncertain from the strongly magenta-lit image
Chert (varietal Flint)
Microcrystalline quartz (SiO2)
Chert (Arrowhead variety)
Chert (SiO2)
Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
Metallic sulfide mineral fragment, likely galena
Galena (lead sulfide, PbS), tentative identification
Green Agate
Silicon dioxide (SiO₂)
Sandstone
Arenite
Green glassy slag (often sold as “sea glass” or “green obsidian”)
Industrial vitreous slag; primarily amorphous silicate glass, composition variable
Possible weathered basalt or slag fragment
Basalt, chiefly plagioclase and pyroxene; identification is uncertain from the image
Chert (likely flint)
Microcrystalline quartz, SiO₂
Chert (Flint)
Silicon dioxide (SiO2)
Hematite Beads
Hematite (Fe2O3)
Man-made Blank Ammunition (Brass)
CuZn (Cartridge Brass - roughly 70% Copper, 30% Zinc)
Opalite (a synthetic glass, often confused with Opal)
Silicon dioxide glass (SiO2nH2O, for natural opal)
Chert (Arrowhead/Tool variety)
Microcrystalline Quartz (SiO2)
Glass / Silicon Dioxide (Man-made)
SiO2 (Amorphous Silicon Dioxide)
Blue sea glass or blue glassy mineral fragment
Uncertain; likely man-made soda-lime glass, not a natural mineral
Sandstone
Arenite (primarily SiO2)