Siltstone
Siltstone (composed of clastic quartz and feldspar grains)
sedimentary
Category
Mineral Based Alloy (Anthropogenic)
Browse mineral based alloy (anthropogenic) specimens identified by the Rock Identifier community.
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Limestone River Cobble
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Basalt
Basalt (extrusive igneous rock)
igneous
Basalt
Mafic Volcanic Rock
igneous
Basalt (Vesicular or Weathered)
Aphanitic Mafic Igneous Rock (Basalt)
igneous
Siltstone
Siltstone (clastic sedimentary rock)
sedimentary
Basalt
Mafic volcanic rock (formula mostly SiO2, MgO, FeO)
igneous
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Basalt with Plagioclase Phenocryst
Porphyritic Basalt
igneous
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Basalt
Basalt (Mafic volcanic rock)
igneous
Basalt (tumbled/water-worn)
Extrusive mafic igneous rock
igneous
Granite
Phaneritic Plutonic Felsic Rock (SiO2 > 63%)
igneous
Basalt
Extrusive mafic igneous rock
igneous
Porphyritic Rhyolite or Andesite (Porphyry)
Porphyritic igneous rock (Composition depends on exact mineralogy, often Rhyolite or Andesite)
igneous
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Basalt
Extrusive mafic igneous rock
igneous
Granite
Granite
igneous
Limestone (River Stone)
Calcite-rich Sedimentary Rock (CaCO3)
sedimentary
Basalt
Basalt (Mafic volcanic rock)
igneous
Basalt Pebble
Basalt
igneous
Basalt River Stone
Basalt (Aphanitic Mafic Volcanic Rock)
igneous
Grey Granite
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Limestone (Calcium Carbonate - CaCO3)
sedimentary
Granite
Granite (Phaneritic Igneous Rock)
Igneous
Basalt Pebble
Basalt (Extrusive Mafic Rock)
igneous
Basalt (Water-worn)
Aphanitic Mafic Igneous Rock
Igneous
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Granitoid Gneiss with Feldspar Vein
Gneiss (High-grade Metamorphic Rock) with Potassium Feldspar (KAlSi3O8)
metamorphic
Rhyolite Pebble
Rhyolite
igneous
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
igneous
Basalt
Basalt
igneous
Limestone
Calcareous sedimentary rock (CaCO3)
sedimentary
Limestone
Sedimentary Calcite (CaCO3)
sedimentary
Siltstone
Siltstone (primarily SiO2 with Al2O3)
sedimentary
Greywacke (River Pebble)
Dirty Sandstone (SiO2 with lithic fragments)
sedimentary
Porphyritic Basalt
Porphyritic Mafic Volcanic Rock
igneous
Andesite Porphyry
Porphyritic Andesite (Intermediate volcanic rock)
igneous
Pink Granite
Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Plagioclase)
igneous