Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Category
Man Made Rock (Technosol)
Browse man made rock (technosol) specimens identified by the Rock Identifier community.
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Sandstone
Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)
sedimentary
Native Silver
Silver (elemental Ag)
mineral
Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Chert (often called Flint)
Chert (Microcrystalline or cryptocrystalline Silica, SiO2)
sedimentary
Nickel coin (U.S. currency)
Cupronickel (75% Copper, 25% Nickel alloy)
man-made alloy (metallic)
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Sandstone
Clastic sedimentary rock (Quartz arenite/Arkose)
sedimentary
Coquina
Biogenic Limestone (CaCO3)
sedimentary
Tumbled quartz-rich pebble
Microcrystalline quartz (SiO₂), possibly milky quartz or quartzite
mineral
Granite
Granite (Phaneritic Quartz-Feldspar intrusive rock)
Igneous
Rounded pink granite cobble
Granite, chiefly quartz–alkali feldspar–plagioclase–biotite
igneous
Chert (Flint / Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Marble
Metamorphic Limestone (CaCO3)
metamorphic
Unakite
Altered Granite (Epidotized Granite)
metamorphic
Fulgarite
Fulgurite (Lechatelierite / Vitrified Sand)
igneous
Turquoise
Turquoise, CuAl6(PO4)4(OH)8·4H2O
mineral
Pink Granite (Alkali-feldspar Granite)
Felsic intrusive igneous rock (composition: KAlSi3O8, SiO2, NaAlSi3O8)
igneous
Lapis Lazuli
Lapis Lazuli (a rock, not a single mineral; primary mineral is Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2
Metamorphic rock
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Granite
Phaneritic Felsic Igneous Rock
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
sedimentary
Polished blue calcite sphere (tentative identification)
Calcite, CaCO₃; blue color generally results from trace impurities or inclusions
mineral
Rounded quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Polished dark gray stone, likely basalt or fine-grained andesite
Basalt/andesite; primarily plagioclase feldspar, pyroxene, and possibly olivine or magnetite
igneous
Goldstone (Synthetic Aventurescence Glass)
Cuprous Aventurescent Glass (Silicon Dioxide with Copper inclusions)
mineraloid / man-made material
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
sedimentary
Likely blue glass or synthetic gemstone jewelry
Uncertain; possibly synthetic spinel, cubic zirconia, or blue glass
gemstone
Limestone
Sedimentary Rock (Primarily CaCO3)
sedimentary
Beach Pebble (Chalcedony / Chert)
Silicon Dioxide (SiO2)
mineral
Chert (Flint)
Microcrystalline quartz (SiO2)
sedimentary
Decorative gemstone-chip jewelry (likely turquoise, coral, and assorted beads)
Predominantly turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; other pieces appear to be dyed coral or red stone, and possibly shell/metal components
gemstone
Sandstone
Arenite (SiO2 principal)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
sedimentary
Riverstone (Sandstone Pebble)
Arenite (SiO2 with various lithic fragments)
sedimentary
Fine-grained gray stone, possibly slate
Slate (fine-grained metamorphosed mudstone); identification is uncertain from the image
metamorphic
Faceted brown gemstone pendant, likely smoky quartz or champagne topaz
Probably quartz (SiO₂), smoky variety; alternatively topaz (Al₂SiO₄(F,OH)₂)
gemstone
Quartzite
Quartzite (Metamorphic Quartz Sandstone)
metamorphic
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
igneous