Basalt
Mafic Volcanic Rock (composed of plagioclase, pyroxene, and olivine)
Category
Browse igneous or metamorphic (base stone); anthropogenic (decoration) specimens identified by the Rock Identifier community.
Basalt
Mafic Volcanic Rock (composed of plagioclase, pyroxene, and olivine)
Biotite Mica
K(Mg,Fe)3AlSi3O10(OH)2
Yellow Quartz or Citrine
Silicon Dioxide (SiO2)
Diorite
Diorite (Intermediate intrusive igneous rock)
Granite
Granite (Phaneritic intrusive igneous rock)
Granite
Granite (Felsic Intrusive Igneous Rock)
Basalt
Mafic Volcanic Rock (composed of plagioclase, pyroxene, and olivine)
Asphalt (Bituminous Concrete)
Asphaltum / Bitumen-Aggregate Matrix
Aquamarine
Beryl (Be3Al2Si6O18)
Basalt
Africite (Mafic Igneous Rock)
Basalt
Extrusive mafic igneous rock
Diorite (River Cobble)
Intermediate plutonic igneous rock
Porphyritic Rhyolite
Porphyritic Rhyolite (compositionally similar to granite)
River Cobble (likely Basalt)
Mafic Igneous Rock (Aphanitic)
Red Jasper
Chalcedony (SiO2) with iron inclusions
Obsidian
Volcanic Glass (predominantly SiO2)
Citrine
Silicon Dioxide (SiO2)
Granodiorite
Granodiorite (Quartz + Plagioclase + Alkali Feldspar + Biotite/Hornblende)
Granite
Granite (Phaneritic Acidic Igneous Rock)
Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
Amethyst (Geode)
Silicon Dioxide (SiO2) with iron impurities
Picture Jasper
Tectonically broken chalcedony (SiO2)
Muscovite Mica
Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2
Diorite
Intermediate plutonic igneous rock
Granite
Granite (Silicic Plutonic Rock)
Basalt
Basalt (Mafic volcanic rock)
Granite (Pink/Red Orthoclase variety)
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
Mica Schist (with Golden/Biotite inclusions)
K(Mg,Fe)3AlSi3O10(F,OH)2 (Biotite), KAl2(AlSi3O10)(F,OH)2 (Muscovite)
Granite (with Orthoclase and Quartz)
Phaneritic Felsic Igneous Rock (KAlSi3O8 + SiO2)
Granite
Phaneritic Felsic Igneous Rock
Sapphire
Corundum (Al2O3)
Milky Quartz Vein with Iron Staining
Silicon Dioxide (SiO2)
Banded Agate (specifically Mexican Lace Agate variety appearance)
Silicon Dioxide (SiO2 / Chalcedony)
Basalt (Gravel Pebble)
Basalt (contains pyroxene, plagioclase feldspar, and olivine)
Granite
Granite (Alkali-feldspar, Quartz, and Plagioclase composition)
Chert (Arrowhead variety)
Chert (SiO2)
Jasper
Silicon dioxide (SiO2) with impurities
Jasper
Silicon Dioxide (SiO2)
Granite
Plutonic Igneous Rock (composed typically of SiO2, Al2O3, K2O, Na2O, CaO)
Granite
Granite (Phaneritic intrusive igneous rock; primarily SiO2 and Al2O3)
Pink Granite
Granite (Felsic Plutonic Rock)
Diorite (Salt and Pepper Rock)
Diorite (comprising Plagioclase Feldspar, Hornblende, and Biotite)