Acrylic or Resin (Synthetic Imitation)
Polymethyl Methacrylate (PMMA) or Polyepoxide
Synthetic/Man-made Polymer
Category
Sedimentary Like (Industrial Composite)
Browse sedimentary like (industrial composite) specimens identified by the Rock Identifier community.
Learn about Sedimentary Like (Industrial Composite) in the encyclopedia
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Quartz (Agate/Chalcedony variety)
Silicon Dioxide (SiO2)
mineral
Grey Chalcedony
Silicon Dioxide (SiO2)
mineral
Schist
Mica Schist
metamorphic
Likely calcite or quartz fragment
Uncertain from image; calcite (CaCO₃) is the leading possibility, with quartz (SiO₂) another possibility
mineral
Tumbled Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
sedimentary
Raw Garnet Fragment
Nesosilicate Group (e.g., Almandine, Fe3Al2(SiO4)3)
mineral
Garnet
Garnet Group (Silicate mineral); general formula X3Y2(SiO4)3
mineral
Weathered greenish rock fragment
Indeterminate; possibly epidote- or chlorite-bearing altered silicate rock
mineral
Opalite
Synthetic Opalite Glass / Opalized Glass
gemstone
Mica Schist
Metamorphic rock dominated by micas (muscovite, biotite)
metamorphic
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Schist
Mica Schist
metamorphic
Sandstone (likely Quartzose)
Arenite (primarily SiO2)
sedimentary
Quartzite
Metamorphosed Quartz Sandstone
metamorphic
Red Shale
Fissile Siliciclastic Sedimentary Rock
sedimentary
Pumice
Pumice (a highly vesicular volcanic rock)
igneous
Quartzite
Quartzite (chiefly SiO2)
metamorphic
Diamond (faceted)
Carbon (C)
gemstone
Faceted Quartz (Rock Crystal)
Crystalline Silicon Dioxide (SiO2)
gemstone
Mica Schist
Mica Schist (primarily Muscovite and Biotite KAl2(AlSi3O10)(OH)2)
metamorphic
Quartzite pebble with Quartz Vein
Metamorphic Quartzite (SiO2) with Quartz Veining
metamorphic
Peacock Ore
Bornite (Cu5FeS4) or Chalcopyrite treated with acid
mineral
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Man-made Glass (Not a natural rock or mineral)
Tumbled Agate and Chalcedony
Cryptocrystalline Quartz (SiO2)
mineral
Blue Sapphire
Corundum (Al2O3)
gemstone
Iron Slag (Industrial Byproduct)
Anthropogenic Vitrification Product/Ferrous Slag
Mineral-like Industrial Smelting Waste
Unakite-like jasper / epidote–feldspar rock
Epidote–feldspar–quartz aggregate; commonly marketed as unakite or brecciated jasper
metamorphic
Sapphire
Corundum (Al2O3)
gemstone
Schist (Mica Schist)
Mica Schist
metamorphic
Kimberlite
Kimberlite (Group I or II)
igneous
Asphalt / Bituminous Aggregate
Bituminous mixture (Hydrocarbon-based sediment)
sedimentary
Coal (Bituminous or Anthracite)
Carbonaceous sedimentary rock (primarily Carbon, C)
sedimentary
Likely tumbled jasper or iron-rich chert
Microcrystalline quartz (SiO₂), potentially hematite/goethite-bearing
mineral
Tumbled Quartz
Silicon Dioxide (SiO2)
mineral
Granitic Pegmatite (River Rock specimen)
Granite / Pegmatite (composed of SiO2, KAlSi3O8, and NaAlSi3O8)
igneous
Ironstone Concretion (Limonite/Goethite)
Ferruginous concretion (Fe2O3·nH2O)
sedimentary
Diamond
Native Carbon (C)
mineral
Milky Quartz with Iron Inclusions
Quartz (Silicon Dioxide, SiO2)
mineral
Red Garnet Gemstone
Pyrope-Almandine Garnet (Mg3Al2(SiO4)3 to Fe3Al2(SiO4)3)
gemstone
Aquamarine
Beryl (Be3Al2Si6O18)
mineral