Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Category
Browse sedimentary (volcanic) specimens identified by the Rock Identifier community.
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Agate
Silicon dioxide (SiO2) - variety Chalcedony
Basalt
Extrusive mafic igneous rock
Peridot (Olivine)
Olivine, (Mg, Fe)2SiO4
Obsidian
Volcanic Glass (Silicon Dioxide with impurities)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Pumice
Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)
Basalt
Mafic Volcanic Rock (composed of plagioclase, pyroxene, and olivine)
Sandstone (Ferruginous)
Arenite (with Goethite/Limonite cement)
Basalt (Vesicular)
Extrusive mafic igneous rock
Basalt (tumbled/water-worn)
Extrusive mafic igneous rock
Banded Agate (Carnelian variety)
Cryptocrystalline Quartz (SiO2)
Basalt with Epidote (Greenstone)
Epidote-bearing Metabasalt
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with inclusions
Vesicular Basalt
Extrusive mafic igneous rock
Basalt River Stones
Aphantic Mafic Igneous Rock (Basalt)
Agate (specifically Botswana or Lake Superior style Agate)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Basalt
Mafic Igneous Rock
Gabbro
Gabbro
Basalt Column Section
Columnar Basalt (Mafic Extrusive Igneous Rock)
Red Scoria (Lava Rock)
Scoria (Vesicular Basalt)
Basalt with Epidote (Porphyry)
Basalt (with inclusions of Epidote/Feldspar)
River Stone (Basalt)
Basalt (Aphanitic Mafic Igneous Rock)
Carnelian Agate
Silicon dioxide (SiO2) - Chalcedony variety
Diamond
Diamond (C)
Milky Quartz with Pyrite inclusions
Silicon Dioxide (SiO2) with Iron Disulfide (FeS2)
Obsidian
Obsidian (Volcanic Glass) SiO2 (70% or more)
Obsidian
Obsidian (Volcanic Glass, ~70% SiO2)
Obsidian
Amorphous Volcanic Glass (primarily SiO2)
Obsidian
Volcanic Glass (70-75% SiO2)
Snowflake Obsidian
Volcanic glass with Spherulite inclusions (SiO2)
Pumice
Pumice (a highly vesicular volcanic rock)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Vesicular Basalt (Amygdaloidal)
Amygdaloidal Basalt (Mafic volcanic rock)
Obsidian
Volcanic Glass (70% or more SiO2)
Obsidian
Volcanic Glass (70-75% SiO2)
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2)
Fossiliferous Limestone with Rugose Coral
Calcite (CaCO3) matrix containing Rugosa (order of extinct solitary and colonial corals)
Olivine (Peridot)
Olivine Group (Mg,Fe)2SiO4
Carnelian Agate
Chalcedony (Silicon Dioxide, SiO2)