Chert
Microcrystalline Quartz (SiO2)
sedimentary
Category
Synthetic Material (Not A Rock Or Mineral)
Browse synthetic material (not a rock or mineral) specimens identified by the Rock Identifier community.
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Sandstone / Weathered Chert
Silicon Dioxide (SiO2) / Quartz-rich Clastic Rock
sedimentary
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (mostly SiO2)
metamorphic
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Sandstone
Arenite (with iron oxide cement)
sedimentary
Siltstone or Fine-grained Sandstone pebble
Siltstone (primarily SiO2 with clay minerals)
sedimentary
Sandstone (with Iron Staining)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
sedimentary
Rounded river cobble, likely basaltic volcanic rock
Fine-grained mafic igneous rock; likely basalt or andesite
igneous
Opal (in Jewelry Setting)
Hydrated Silicon Dioxide (SiO2·nH2O)
gemstone
Conglomerate
Conglomerate (Sedimentary Clastic Rock)
sedimentary
Serpentinized ultramafic rock (likely serpentinite)
Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, olivine, pyroxene, and sulfides
metamorphic
Basalt
Basalt (Ma-Fe Silicate)
igneous
Chert / Flint (Yellow Jasper Variant)
Microcrystalline Quartz (SiO2 with Iron Oxide impurities)
sedimentary
Turquoise and Red Coral
Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)
mineral
Limestone with Calcite Veins
Calcium Carbonate (CaCO3) - Sparry Limestone
sedimentary
Chert (Holey Stone)
Microcrystalline Quartz (SiO2)
sedimentary
Pink Granite
Phaneritic intrusive igneous rock with dominant Alkali Feldspar
igneous
Dalmatian Stone and Lapis Lazuli
Dalmatian Stone (peralkaline rock) with Lapis Lazuli (metamorphic rock)
igneous
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Siltstone/Sandstone (possibly Wonderstone or Picture Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Iron Oxide inclusions)
Sedimentary
Mica Schist
Mica Schist (Quartz-Biotite-Muscovite Schist)
metamorphic
Greywacke (River Pebble)
Greywacke sandstone with quartz veining
sedimentary
Granite
Granite (composed mainly of Quartz, Feldspar, and Mica)
igneous
Serpentine
Serpentinite (rock) containing serpentine minerals (e.g., Antigorite, Lizardite, Chrysotile)
Metamorphic rock
Rhodonite-bearing metamorphic rock
Manganese-rich metamorphic rock, chiefly rhodonite (MnSiO₃), with quartz and manganese oxides
metamorphic
Basalt
Basalt (Mafic volcanic rock)
igneous
Weathered iron-stained quartzite or sandstone cobble
Quartzite (quartz-rich rock), possibly ferruginous sandstone
metamorphic
Red Sandstone
Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)
sedimentary
Coal (Bituminous / Anthracite)
Carbonaceous Sedimentary Rock (C)
sedimentary
Banded Siltstone
Siltstone with planar bedding
sedimentary
Sandstone
Arenite
sedimentary
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
mineral
Agate
Silicon Dioxide (Chalcedony), SiO2
gemstone
Red Sandstone
Sandstone (lithic arenite / ferruginous sandstone)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
sedimentary
Fossil Coral
Scleractinia (Fossilized Hexacoral)
fossil
Conglomerate
Conglomerate rock
sedimentary
Veined quartz-bearing metamorphic rock
Likely quartzite or siliceous schist with iron-oxide staining
metamorphic
Pink Granite / Gneiss Pebble
Quartz-Feldspar Granitic Rock
igneous
Polished copper-bearing rock, likely cuprite-rich copper ore
Cuprite (Cu₂O) with native copper and iron-oxide matrix, probable
mineral
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3(Si, Al, Fe)2O5(OH)4
metamorphic