Granite
Granite (Felsic Plutonic Rock)
Category
Browse anthropogenic (man made material) specimens identified by the Rock Identifier community.
Granite
Granite (Felsic Plutonic Rock)
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
Goldstone (blue-goldstone–style glass) beads
Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral
Chert (often called Flint or Agate nodule)
Cryptocrystalline Quartz (SiO2)
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
Diamond
Carbon (C)
Jasper
Silicon Dioxide (SiO2)
N/A - Man-made object (Jewelry Chain)
Antiqued or Oxidized Metal Chain (often Steel or Brass)
Man-made Jewelry Charm (Enameled Metal)
Not a natural mineral; composed of base metal alloy (likely zinc or brass) and epoxy resin/enamel.
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (often called Flint)
Chert (SiO2)
Sandstone
Arenite
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
Green Slag Glass
Cullet (Amorphous Silicon Dioxide with impurities)
Graphite
Graphite (Carbon, C)
Sandstone
Arenite
Sandstone (Pebble)
Sandstone (arenite, arkose, wacke depending on composition)
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / 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)
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Chipped Glass/Plastic Fragment
Silicon dioxide (SiO2) for glass (amorphous) or various polymer compounds for plastic
Man-made Green Quartz (Lab-grown or Treated)
Silicon Dioxide (SiO2) with artificial coloration
Petrified Wood
Silicified Wood (SiO2)
Iron Slag
Ferrous Slag (Industrial Byproduct)
Diamond (Faceted)
Carbon (C)
White Marble
Recrystallized Calcite Rock (CaCO3)
Chert / Green Jasper
Silicon Dioxide (SiO2)
Diorite (River Pebble)
Intermediate Phaneritic Igneous Rock
Iron Slag
Ferrous Slag (Silicate/Oxide mixture)
Blue glass-like tumbled specimen
Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image
Slag
Anthropogenic Vitreous Silicate / Ferro-silicate Slag
Painted River Pebble (likely Basalt or Greywacke)
Aphanitic Lithic Clast with Anthropogenic Pigment coating
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Coquina
Bioclastic Limestone (Calcium Carbonate, CaCO3)
Banded Sandstone
Arenite with Liesegang banding
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
Tumbled amber-colored chalcedony or jasper
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper
Diamond
Carbon (C)
Flint (or Chert with cortex)
Silicon dioxide (SiO2)
Chert (varieties include Flint and Mudstone)
Microcrystalline Silica (SiO2)