Obsidian
Volcanic glass
Category
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Obsidian
Volcanic glass
Obsidian
Volcanic glass
Obsidian
Volcanic glass
Basalt River Pebble
Mafic Igneous Rock (Fine-grained Basalt)
Basalt with Secondary Mineral Inclusions
Amygdaloidal Basalt (Mafic volcanic rock, primarily Augite and Plagioclase)
Scoria (Red Lava Rock)
Scoria
Amygdaloidal Basalt
Amygdaloidal Basalt (extrusive volcanic rock)
Basalt with Iron Oxidation (Lattice/Veined)
Mafic Volcanic Rock (principally Plagioclase and Pyroxene)
Quartz in Basalt (Xenocryst)
Silicon Dioxide (SiO2) in Mafic Igneous Volcanic Rock
Milky Quartz with Mineral Inclusions
Silicon Dioxide (SiO2) with miscellaneous inclusions
Basalt (Weathered Pebble)
Extrusive mafic igneous rock; minerals primarily Plagioclase feldspar and Pyroxene
Amygdaloidal Basalt with Epidote/Chlorite
Basalt (containing (Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH)))
Druzy Quartz on Vesicular Basalt
Silicon Dioxide (SiO2) in an extrusive Mafic igneous host rock
Porphyry (likely Porphyritic Andesite or Basalt)
Porphyritic Igneous Rock
Basalt
Mafic Igneous Rock
Obsidian
Volcanic glass
Basalt (River Pebble)
Basalt
Basalt
Basalt (Mafic volcanic rock)
Basalt
Basalt (Igneous Volcanic Rock)
Obsidian (likely Golden Sheen Obsidian or Rainbow Obsidian, given the subtle sheen visible on some beads)
Obsidian (volcanic glass, predominantly SiO2 with various impurities)
Basalt (Weathered/River worn)
Mafic Volcanic Rock (Primarily Plagioclase Feldspar and Pyroxene)
Porphyritic Basalt (Chinese Writing Stone)
Porphyritic Basalt or Porphyritic Andesite
Quartz (Druzy)
Silicon Dioxide (SiO2)
Basalt River Stone
Basalt
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Amygdaloidal Basalt
Amygdaloidal Basalt containing Zeolite and Calcite inclusions
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock)
Basalt (River-worn Specimen)
Extrusive Mafic Igneous Rock
Amethyst
Silicon Dioxide with Iron impurities (SiO2)
Basalt Pebble
Extrusive mafic igneous rock; primarily (Ca, Na)(Mg, Fe, Al)Si2O6 and (Ca, Na)AlSi3O8
Amygdaloidal Basalt
Amygdaloidal Basalt
Vesicular Basalt
Amygdaloidal Basalt (Mafic extrusive volcanic rock)
Jasper and Basalt Mix (Dark Chert/Basalt River Pebble)
Silicon Dioxide (SiO2) or Mafic extrusive igneous rock
Basalt
Extrusive mafic igneous rock
Basalt (Weathered)
Extrusive mafic volcanic rock
Basalt
Basalt (composition of plagioclase feldspar and pyroxene)
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
Vesicular Basalt with Quartz/Chalcedony
Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)
Basalt
Extrusive mafic igneous rock
Smoky Quartz and Chalcedony Geode Fragment
Silicon Dioxide (SiO2)
Quartz on Matrix
Silicon Dioxide (SiO2)