Quartzite (specifically a river-worn pebble)
Quartzite (primarily SiO2)
metamorphic
Category
Sedimentary Rock (Specifically A Concretion Or Possibly A Geode)
Browse sedimentary rock (specifically a concretion or possibly a geode) specimens identified by the Rock Identifier community.
Basalt
Extrusive mafic igneous rock
igneous
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Basalt
Basalt
igneous
Basalt
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Chert (specifically Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Sedimentary
Basalt (Crushed Stone Aggregate)
Mafic Volcanic Basalt (Major Minerals: Plagioclase Feldspar, Pyroxene, Olivine)
igneous
Basalt with Iron Oxides
Mafic Igneous Rock (Mafite)
igneous
Basalt with Quartz Veining
Amygdaloidal Basalt (predominately SiO2 and (Na,Ca)(Si,Al)4O8)
igneous
Basalt
Extrusive mafic igneous rock
igneous
Riverstone Quartzite (Water-worn Siltstone/Quartzite)
Metamorphosed Quartz-rich Arenite (SiO2)
metamorphic
Andesite Porphyry
Porphyritic Andesite
igneous
Red Scoria (Lava Rock)
Vesicular Basalt / Scoria
igneous
Basalt (Vesicular or Porphyritic)
Basalt (composed primarily of plagioclase feldspar, pyroxene, and olivine)
igneous
Green Calcite
Calcite (CaCO3)
mineral
Chert (Red Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Shale or Argillite
Shale (sedimentary) / Argillite (metamorphic)
Sedimentary or Metamorphic (low-grade)
Ferrous Slag (Iron Smelting By-product)
Fused Siliceous Slag
Anthropogenic Material (Man-made Rock)
Scoria (Lava Rock)
Mafic extrusive volcanic rock (Scientific formula varies based on mineral content: primarily SiO2, MgO, and FeO)
igneous
Pumice
Pumice (Vitreous volcanic rock)
igneous
Moss Agate
Silicon Dioxide with inclusions (SiO2 + impurities)
mineral
Scoria (Lava Rock)
Scoria (Vesicular Basaltic Rock)
Igneous
Scoria (Vesicular Basalt)
Scoria (Extrusive Igneous Rock)
igneous
Scoria (Red Lava Rock)
Scoria (Vesicular basaltic rock)
Igneous
Basalt
Basalt (Mafic Extrusive)
igneous
Basalt River Cobble
Vitreous aphanitic Basalt
igneous
Synthetic Faux Fur Fursuit
Polyacrylonitrile / Polyester (Synthetic Textile)
not a rock (synthetic material/costume)
Quartz (specifically Milky Quartz/Quartzite)
Silicon Dioxide (SiO2)
Mineral
Basalt
Basalt
igneous
Yellow Jasper
Chalcedony (SiO2) with goethite or limonite inclusions
sedimentary
Basalt
Basalt (Mafic Extrusive)
igneous
Granite (specifically Rapakivi Granite)
Phaneritic Felsic Igneous Rock (Granite)
igneous
Basalt Beach Pebble
Basalt (Aphanitic Mafic Volcanic Rock)
igneous
Basalt
Extrusive mafic igneous rock
igneous
Basalt with Quartz/Plagioclase Inclusions
Mafic volcanic rock (Basaltic)
igneous
Scoria (Lava Rock)
Scoria (Vesicular Basaltic Glass/Rock)
igneous
Amethyst Geode (polished heart-cut)
Silicon Dioxide (SiO2) with iron impurities
mineral
Jasper (specifically Oolitic or Brecciated Jasper)
Silicon Dioxide (SiO₂)
sedimentary
Puddingstone (specifically Gowganda Tillite or St. Joseph Island Puddingstone)
Jasper Conglomerate
sedimentary
Chert (specifically as a lithic artifact/projectile point)
Chert (Silicon dioxide, SiO2)
sedimentary
Moss Agate
Chalcedony (SiO2) with dendritic inclusions of Manganese or Iron oxide
mineral