Sandstone
Sandstone (Quartz-rich Arenite / SiO2)
sedimentary
Category
Man Made Material (Anthropogenic 'Mineraloid')
Browse man made material (anthropogenic 'mineraloid') specimens identified by the Rock Identifier community.
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Green Quartzite
Metamorphic Quartzite (often colored by chromium-bearing minerals or fuchsite)
metamorphic
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Sunstone (Aventurine Feldspar)
(Ca,Na)((Al,Si)2Si2O8) with inclusions of Cu or Fe2O3
mineral
Iron-stained quartz-rich rock, possibly jasper or chert
Microcrystalline quartz (SiO₂) with iron oxides/hydroxides
mineral
Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks
Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock
sedimentary
Pearls
Aragonite (calcium carbonate) and Conchiolin
Mineraloid
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
sedimentary
Flint
Silicon dioxide (SiO2)
sedimentary
Chert
Microcrystalline Silicon Dioxide (SiO2)
sedimentary
Quartz (Microcrystalline/Chert)
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Silicon dioxide (SiO2)
sedimentary
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Chert (Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
mineral and glass
Tektite
Natural impact glass
meteorite
Coquina
Coquina (Biogenic Limestone / CaCO3)
sedimentary
Chert (often called Flint or Jasper if reddish)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Chalk
Calcite (CaCO3)
sedimentary
Sandstone
Arenite
sedimentary
Sandstone (Quartzose)
Arenite (primarily SiO2)
sedimentary
Chert (with nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone (with potential Arkose/Lithic characteristics)
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Ferrochrome Slag
Anthropogenic silicate/oxide glass (Complex silicate matrix with Cr-Fe-Si inclusions)
Industrial byproduct (often confused with igneous rocks or meteorites)
Polished greenstone pebble
Likely nephrite jade (tremolite–actinolite), though serpentine or greenstone is possible from appearance alone
metamorphic
Chert / Flint
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint)
Microcrystalline Silica (SiO2)
sedimentary
Coquina
Biogenic Limestone (Coquina)
sedimentary
Sandstone
Arenite (SiO2 composition dominant)
sedimentary
Sandstone (Quartz Arenite)
Sandstone (dominated by SiO2 quartz grains)
sedimentary
Chalk
Carbonate rock (mainly CaCO3)
sedimentary
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Man-made Glass (Not a natural rock or mineral)
Tumbled epidote-bearing rock (likely epidote–quartz–feldspar aggregate)
Epidote-rich metamorphic rock; minerals likely epidote (Ca₂(Al,Fe)₃Si₃O₁₂(OH), quartz, feldspar, and dark amphibole/biotite)
metamorphic
Quartzite
Metamorphic quartz rock (SiO2)
metamorphic
Ferrochrome Slag
Industrial Glassy Slag (Fe-Cr alloy byproduct)
Antropogenic (Man-made industrial byproduct)
Beach Pebble (Chalcedony / Chert)
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (with iron oxide cement)
sedimentary
Chert (Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (often called Flint or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary