Basalt
Basalt (Mafic Extrusive)
igneous
Category
Man Made (Synthetic Rock)
Browse man made (synthetic rock) specimens identified by the Rock Identifier community.
Chert (Tan/Grey variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Basalt
Basalt (Mafic volcanic rock)
igneous
Sandstone (Gneissic or Banded)
Clastic Sedimentary Rock (composed predominantly of SiO2)
sedimentary
Sandstone (Quartzose Sandstone)
Clastic Sedimentary Rock (Lithic arenite / Quartz arenite)
sedimentary
Epidote (or Epidote-rich rock)
Epidote. Mineral formula: Ca2(Al,Fe)3(SiO4)3(OH).
Mineral, often found in metamorphic rocks but also in sedimentary and igneous rocks
Basalt
Extrusive Mafic Igneous Rock
igneous
Garnet-Bearing Gneiss
Almandine-Garnet Gneiss
metamorphic
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Clastic sedimentary rock (primarily SiO2)
sedimentary
Granite (Weathered)
Plutonic Igneous Rock (Granitic)
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
River Cobble (likely Sandstone or Siltstone type)
Sandstone or Siltstone (common rock types that form river cobbles)
Sedimentary Rock (specifically a clastic sedimentary rock formed into a cobble)
Sandstone (likely Quartz Sandstone)
Arenite (composed primarily of SiO2)
sedimentary
Basalt
Basalt (composition mainly of Plagioclase feldspar, Pyroxene, and Olivine)
igneous
Sandstone (likely Quartzose Sandstone with mineral staining)
Arenite (composed mainly of SiO2)
sedimentary
Chert (specifically Flint)
Microcrystalline quartz (SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite with Iron Oxides
sedimentary
Sandstone (likely Ferruginous)
Arenite (SiO2 with iron oxide impurities)
sedimentary
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Quartzite River Rock
Quartzite (Silicon Dioxide, SiO2)
metamorphic
Granite (Phaneritic Igneous Rock)
Granite
igneous
Scoria (Basaltic)
Vesicular Basalt
igneous
Quartz Vein / Milky Quartz
Silicon Dioxide (SiO2)
mineral
Drill Core Sample
Cylindrical Rock Core (Specific mineralogy varies by extraction site)
Metamorphic (Likely Gneiss or Schist based on texture)
Orthoclase Feldspar
Potassium Aluminum Silicate (KAlSi3O8)
mineral
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Metamorphic
Pumice
Pumiceous rhyolite
igneous
Granite Sand (Decomposed Granite)
Grus / Quartz-Feldspar Detritus
sedimentary
Sandstone (River Pebble)
Arenite (SiO2 based)
sedimentary
Granite
Granite (composed primarily of Quartz SiO2 and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8))
igneous
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety often found as a river rock)
Metamorphic Rock
Pumice
Vesicular volcanic glass (primarily SiO2)
igneous
Kimberlite
Kimberlite
igneous
Peridotite (with Olivine)
Peridotite (rich in Olivine, (Mg,Fe)2SiO4)
igneous
Mica Schist
Crystalline Schist (often containing Muscovite, Biotite, and Quartz)
metamorphic
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
igneous