Basalt
Basalt (Mafic volcanic rock)
Category
Browse igneous and sedimentary specimens identified by the Rock Identifier community.
Basalt
Basalt (Mafic volcanic rock)
Pumice
Felsic Volcanic Glass / Vesicular Rhyolite
Basalt (Road Gravel)
Aphanitic mafic volcanic rock (various compositions of plagioclase feldspar and pyroxene)
Basalt
Mafic Volcanic Rock (composed of plagioclase, pyroxene, and olivine)
Granite Cobble
Granite (Phaneritic Quartz-Feldspar Felsic Rock)
Peridotite (Dunite)
Peridotite (mostly Olivine: (Mg,Fe)2SiO4)
Amygdaloidal Basalt
Amygdaloidal Basalt (containing secondary minerals like Quartz, Zeolites, or Calcite)
Obsidian
Volcanic Glass (predominantly SiO2 – Silicon Dioxide, but non-crystalline)
Pumice (likely weathered/water-worn)
Vesicular volcanic glass
Obsidian
Obsidian (Volcanic Glass)
Basalt
Basalt
Basalt
Mafic volcanic rock (Primarily Plagioclase Feldspar and Pyroxene)
Granite
Granite (Felsic Plutonic Rock)
Granite
Granite (Mainly Quartz, Feldspar, and Mica)
Basalt
Basalt
Pumice
Pumiceous rhyolite
Obsidian
Volcanic Glass (SiO2 rich)
Snowflake Obsidian (or similar porphyritic volcanic rock)
Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)
Obsidian
Volcanic Glass (Primary component: SiO2)
Scoria (Basaltic Lava Rock)
Vesicular Basalt
Basalt with Quartz/Calcite matrix
Basalt (SiO2 with Ca/Mg/Fe silicates) on a Mineral Matrix
Granite
Granite (Felsic Plutonic Rock)
Obsidian
Volcanic glass (SiO2 + impurities)
Basalt
Mafic volcanic rock, primarily composed of Plagioclase, Pyroxene, and Olivine
Mahogany Obsidian
Volcanic Glass (Silicate: SiO2 + Fe2O3)
Quartz in Matrix (possibly with Biotite or Hornblende)
Quartz (Silicon Dioxide, SiO2) in Granitic Matrix
Pumice (specifically a water-worn, weathered variety)
Vesicular volcanic glass
Diorite
Diorite
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Basalt
Basalt (composition of Plagioclase feldspar, Pyroxene, and Olivine)
Obsidian
Obsidian (principally SiO2)
Granite
Granite (composed of Quartz, Alkali Feldspar, and Plagioclase)
Basalt River Stone
Basalt
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Pumice
Pumiceous rhyolite / Volcanic glass
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Basalt
Basalt (containing mainly Plagioclase feldspar and Pyroxene)
Basalt
Basalt
Obsidian
Obsidian (Volcanic Glass)
Scoria (Lava Rock)
Scoriaceous Basalt
Basalt with Epidote Veining
Basalt (Mafic Extrusive Rock) with Ca2(Al,Fe)3(SiO4)3(OH)
Granite
Granite (Mainly Quartz, Feldspar, and Mica/Amphibole)