Basalt River Pebble
Basalt
Category
Browse igneous (anthropogenic) specimens identified by the Rock Identifier community.
Basalt River Pebble
Basalt
Andesite Porphyry (River Cobble)
Porphyritic Andesite
Basalt
Basalt (Mafic volcanic rock)
Granitic Pegmatite with Schorl Tourmaline
Granitic Pegmatite (Schorl: NaFe3Al6(BO3)3Si6O18(OH)4)
Tektite (Indochinite)
Tektite (Amorphous Meteoritic Glass)
Granite
Granite (Felsic Plutonic Rock)
Obsidian
Obsidian (Volcanic Glass)
Porphyritic Rhyolite
Porphyritic Rhyolite
Scoria
Scoria (Vesicular Basaltic Glass)
Basalt
Basalt (containing Pyroxene, Plagioclase feldspar, and Olivine)
Quartz with Mica inclusion
Silicon Dioxide (SiO2) with Muscovite/Biotite inclusions
Pumice
Pumice (Alveolar Rhyolite / Dacite / Andesite)
Basalt with Quartz/Calcite Inclusions
Mafic Volcanic Rock (Fe-Mg silicate rich)
Pumice
Pumicite
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Obsidian
Obsidian (Volcanic glass), 70-75% SiO2
Tektite (Indochinite)
Tektite (High-silica natural glass)
Lava Rock (Scoria)
Scoria (Vesicular Basalt)
Granite
Granite (composed primarily of Quartz SiO2, Alkali Feldspar, and Plagioclase Feldspar)
Obsidian
Volcanic Glass (SiO2 + impurities)
Vesicular Basalt (Scoria)
Vesicular Basalt
Obsidian
Obsidian (Extrusive Volcanic Glass)
Granite (Weathered)
Granite (Felsic Plutonic Rock)
Basalt (with Plagioclase Phenocrysts)
Porphyritic Basalt
Basalt Pebble
Extrusive mafic igneous rock; primarily (Ca, Na)(Mg, Fe, Al)Si2O6 and (Ca, Na)AlSi3O8
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (70–75% SiO2)
Quartz Vein in Host Rock
Quartz (SiO2) in Mafic or Sedimentary Matrix
Graphic Granite
Pegmatitic Quartz-Feldspar Granite
Granite
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
Diorite (Salt and Pepper Rock)
Diorite
Basalt
Basalt
Pumice
Pumicite (fine-grained pumice), Scoria (similar origin but denser and darker, usually basaltic)
Basalt River Cobble
Vitreous aphanitic Basalt
Granite Cobble
Phaneritic Plutonic Felsic Rock
Snowflake Obsidian
Volcanic Glass with Spherulite Inclusions (70-75% SiO2)
Obsidian / Volcanic Glass
Obsidian (principally SiO2, usually 70% or more)
Basalt with Vesicular Texture
Basalt (SiO2 range 45-52%)
Granite
Granite (composed primarily of Quartz, Feldspar, and Mica)
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide) with impurities
Porphyry (Flower Stone)
Porphyritic Basalt or Andesite
Scoria (Lava Rock)
Vesicular Basalt / Scoria
Scoria (Vesicular Basalt)
Vesicular Basalt