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)
Category
Anthropogenic (Man Made Material Mimicking Sedimentary Rock)
Browse anthropogenic (man made material mimicking sedimentary rock) specimens identified by the Rock Identifier community.
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Quartz Geode/Druzy Quartz
Quartz (SiO₂)
Mineral
Aura Quartz
Titanium or Gold bonded Silicon Dioxide (SiO2)
mineral
Coal (most likely Bituminous or Anthracite)
Bituminous Coal (Grade of Coal), Anthracite (Grade of Coal)
Sedimentary Rock
Tumbled milky quartz pebble
Quartz (silicon dioxide, SiO₂), opaque-to-translucent milky variety
mineral
Green Aventurine
SiO2 (Silicon Dioxide with Fuchsite inclusions)
mineral
Quartz (possibly milky quartz)
Quartz (Silica; SiO₂)
Mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Cobalt Blue Slag Glass
Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives
mineraloid
Green cabochon gemstone, likely aventurine or dyed chalcedony
Indeterminate from image; possible quartz variety (SiO₂), including aventurine quartz or chalcedony
gemstone
Quartz (likely milky quartz or a stained variety)
Silicon Dioxide (SiO₂)
Mineral
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Mineral
Pumice
Pumice (volcanic rock)
Igneous
Cubic Zirconia (Jewelry Setting)
Cubic Zirconia (ZrO2)
gemstone
Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
mineral
Opalite Egg
Synthetic Glass (Simulated Opal)
mineral
Clear Quartz (or Rock Crystal)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Marble
Marbles are primarily composed of calcite (calcium carbonate, CaCO3) or dolomite (calcium magnesium carbonate, CaMg(CO3)2).
Metamorphic Rock
Green Obsidian Sphere (man-made glass)
Vitreous Silica with Chromium/Iron additives
mineralogical simulant
Quartz
Quartz (SiO₂)
Mineral
Chalk
Calcareous Ooze (composed primarily of coccoliths)
Sedimentary Rock
Goldstone (Brown)
Aventurine Glass (Silicon Dioxide infused with Copper crystals)
mineraloid (man-made glass)
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2
metamorphic
Titanium Aura Quartz
Titanium-coated Silicon Dioxide (SiO2)
mineral
Green Quartz / Chrysoprase / Sea Glass
Silicon Dioxide (SiO2)
mineral
Aura Quartz
Silicon Dioxide (SiO2) with metallic vapor coating
mineral
Sea Glass
Amorphous silicon dioxide (man-made glass weathered by nature)
mineral
Chakra Stone Tower (Composite Multi-Mineral)
Crystalline Silicon Dioxide composite (SiO2) with various inclusions
mineral
Aura Quartz (Titanium-coated Quartz)
Silicon Dioxide (SiO2) with metallic vapor coating
mineral
Engineerged Quartz (Quartz Composite)
SiO2 (Silicon Dioxide) in a polymer resin matrix
mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Chert (Flint)
Chert (predominantly SiO₂ - silicon dioxide)
sedimentary
Quartzite
Quartzite (SiO2)
Metamorphic
Aquamarine and clear quartz
Aquamarine (Be3Al2Si6O18), Quartz (SiO2)
Mineral
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Aura Quartz (Titanium/Rainbow Quartz)
SiO2 (Silicon Dioxide) with metallic coating
mineral
Aura Rose Quartz
SiO2 (Silicon Dioxide with Titanium/Gold coating)
mineral
Marble
Metamorphosed Limestone/Dolomite
metamorphic
Silicon Carbide (Carborundum)
Silicon Carbide (SiC) / Moissanite (natural)
mineral
Opalite
Synthetic Glass (typically Silica/Magnesium based with metal additives)
mineral
Bismuth Crystal
Bismuth (Bi)
mineral
Opalite
Synthetic Glass (SiO2 + impurities)
mineral