Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Sedimentary Rock
Category
Synthetic Polymer (Synthetic Material)
Browse synthetic polymer (synthetic material) specimens identified by the Rock Identifier community.
Quartz
Silicon Dioxide (SiO₂)
Mineral
Quartz (Milky Quartz)
Quartz (SiO2 - Silicon Dioxide)
Mineral
Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Quartz
Silicon Dioxide (SiO₂)
Mineral
Quartz (likely Milky Quartz)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Chert (Flint)
Chert (predominantly SiO₂ - silicon dioxide)
sedimentary
River Cobble (likely Sandstone or Siltstone type)
Sandstone or Siltstone (common rock types that form river cobbles)
Sedimentary Rock (specifically a clastic sedimentary rock formed into a cobble)
Transit Token (RTD Denver)
Nickel-plated brass or bronze alloy (Cu-Sn-Zn-Ni)
not a rock or mineral (anthropogenic material)
Iron Slag
Iron/Steel Slag (Ferrosilicate Glass)
industrial byproduct (anthropogenic material)
Opalite (Man-made Glass)
Fused glass (typically made of dolomite and metal opacifiers)
Man-made Material / Glass
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Sedimentary
Greisen
Greisen
Metamorphic
Calcite
Calcite (CaCO3)
mineral
Obsidian
Obsidian (volcanic glass)
Igneous
Chert (or possibly Flint)
Chert (variant: Flint)
Sedimentary
Turquoise (beads)
Turquoise; CuAl6(PO4)4(OH)8·4H2O
Mineral
Chalcedony (Banded/Mottled Variety)
Chalcedony (a cryptocrystalline variety of Quartz, SiO2)
Mineral
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Igneous Rock
Milky Quartz
Quartz (SiO₂)
Mineral
Gneiss
Gneiss (a rock type, not a specific mineral with a formula)
Metamorphic Rock
Quartz (River Pebble)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Quartz (possibly milky quartz)
Quartz (Silica; SiO₂)
Mineral
Quartzite
Quartzite
Metamorphic rock
Calcite
Calcite (Mineral, Calcium Carbonate - CaCO3)
Mineral
Red Jasper
Jasper (a variety of Chalcedony, SiO₂ with iron oxide inclusions)
Mineral
Banded Gneiss
Gneiss (pronounced 'nice')
metamorphic
Muscovite Mica
Muscovite (KAl₂(AlSi₃O₁₀)(F,OH)₂))
Mineral
Quartz
Quartz (SiO₂ - Silicon Dioxide)
mineral
Serpentinite (Serpentine Rock)
Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.
Metamorphic
Talc
Talc (Mg₃Si₄O₁₀(OH)₂)
Mineral
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral, often found as detrital grains in sedimentary rocks
Muscovite Mica
Muscovite (Potassium Mica) KAl2(AlSi3O10)(OH)2
Mineral
Basalt
Basalt (dominated by plagioclase feldspar and pyroxene)
igneous
Calcite
Calcite (Mineral; CaCO₃)
Mineral
Fluorite (likely)
Calcium Fluoride (CaF2)
Mineral
Fluorite
Fluorite (Calcium Fluoride - CaF2)
mineral
Conglomerate
Conglomerate
Sedimentary Rock
Mica (likely Muscovite)
Muscovite / KAl2(AlSi3O10)(OH)2
mineral
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Mineral
Ferrous Slag (Iron Smelting By-product)
Fused Siliceous Slag
Anthropogenic Material (Man-made Rock)