Calcite
Calcite (Mineral; CaCO₃)
Category
Browse mineraloid like synthetic material specimens identified by the Rock Identifier community.
Calcite
Calcite (Mineral; CaCO₃)
Metal Alloy (Likely Pewter or Sterling Silver)
Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).
Black Obsidian
Volcanic Glass (70–75% SiO2 plus MgO, Fe3O4)
Obsidian
Volcanic Glass (predominantly SiO2)
Blue Chalcedony and Picture Jasper Beads
Blue Chalcedony (SiO2), Picture Jasper (SiO2)
Green Calcite
Calcite (Calcium Carbonate, CaCO3)
Quartzite (Yellow/Tan)
Metamorphic Rock composed of Quartz (SiO₂)
Basalt
Extrusive mafic igneous rock
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
Coquina
Biogenic Limestone (Calcium Carbonate - CaCO3)
Quartzite
Quartzite (primarily SiO2)
Pyrite (on host rock)
Iron Sulfide (FeS2)
Coquina
Coquina (Bioclastic Limestone)
Quartzite
Quartzite (primarily SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Limestone
Calcium Carbonate (CaCO3)
Quartz (Milky or Cloudy variety)
Silicon Dioxide (SiO2)
Pyrite
Iron Disulfide (FeS2)
Quartz (possibly milky quartz)
Quartz (Silica; SiO₂)
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Amethyst Geode/Cluster
Quartz (SiO2) - variety Amethyst
Obsidian
Obsidian (Volcanic Glass)
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Sea Glass (specifically Frosted White)
Amorphous Silica (substance: Sodium-calcium silicate glass)
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Jasper (Red/Yellow)
Silicon Dioxide (SiO2) with impurities
Red Jasper (beads)
SiO₂ (Silicon Dioxide)
Pebble (river rock/beach pebble)
Pebble (clast size class)
Quartz
Silicon Dioxide (SiO₂)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Quartzite
Quartzite (primarily SiO2)
Jasper (specifically variegated or swamp jasper beads)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Olivine (likely Peridot variety)
Olivine Mineral Group (specifically Forsterite-Fayalite solid solution series); Chemical formula: (Mg,Fe)2SiO4
Basalt with Plagioclase Phenocrysts
Porphyritic Basalt
Green Aventurine
Aventurine (a variety of Quartz, SiO2)
Green Sea Glass
Amorphous Silica (man-made glass), SiO2 + additive metal oxides
River Quartzite Spheroid
Recrystallized Orthoquartzite (SiO2)
Biotite Schist
Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
Mica Schist
Mica Schist (Complex Silicate Rock)
Fossil Coral
Coral Limestone (a type of biogenic sedimentary rock)
Shale or Argillite
Shale (fine-grained clastic sedimentary rock) or Argillite (low-grade metamorphic rock derived from shale)