Quartz (White/Milky with Iron Staining)
Silicon Dioxide (SiO2)
Category
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Quartz (White/Milky with Iron Staining)
Silicon Dioxide (SiO2)
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Obsidian
Obsidian (principally SiO2)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Wonderstone (Banded Rhyolite)
Rhyolite (Silicon Dioxide with Iron Oxide impurities)
Pumice
Pumice (a highly vesicular volcanic rock)
Basalt
Basalt
Basalt
Basalt (Mafic volcanic rock)
Apache Tears (Obsidian)
Volcanic Glass (SiO2 - Silicon Dioxide with impurities)
Apache Tear
Obsidian (Hydrated Silica Rich Volcanic Glass)
Apache Tear
Obsidian (Hydrated Volcanic Glass) - SiO2 (with impurities)
Peridot in Basalt
Olivine ((Mg, Fe)2SiO4) in Basalt
Basalt
Basalt (Mafic Extrusive Igneous Rock)
Basalt with Quartz Vein
Mafic Igneous Rock (SiO2 filling)
Chalcedony (Agate/Carnelian precursor)
Chalcedony (Silicon Dioxide, SiO2)
Mahogany Obsidian
Volcanic Glass (with inclusions of Magnetite or Hematite)
Olivine in Basalt matrix
Peridotite (Mg, Fe)2SiO4
Amethyst
Crystalline Quartz (SiO2) with iron impurities
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Obsidian
Obsidian (Volcanic Glass, primarily SiO2)
Basalt (Lava Rock) and Dyed Glass/Quartz
Scoria (Vesicular Basalt)
Basalt Pebble
Basalt
Basalt with Quartz Veins
Basalt (complex silicate) with Quartz (SiO2) intrusions
Pumice
Highly vesicular volcanic glass (unnamed scientific variant: Rhyolitic/Andesitic Pumice)
Quartz Geode
Silicon Dioxide (SiO2)
Obsidian (Arrowhead Lithic Tool)
Obsidian (Amorphous Volcanic Glass / SiO2 + inclusions)
Pumice
Pumicite (fine-grained pumice), Scoria (similar origin but denser and darker, usually basaltic)
Pumice
Pumice (a highly vesicular extrusive igneous rock, primarily amorphous silica)
Rough Agate/Chert Nodules
Cryptocrystalline Quartz (SiO2)
Quartz on Host Rock
Silicon Dioxide (SiO2)
Amygdaloidal Rhyolite
Rhyolite (felsic volcanic rock) with amygdules
Pumice
Pumice (a highly vesicular amorphous silicate glass)
Rough Amethyst
Silicon Dioxide (SiO2) with Iron impurities
Amethyst
Amethyst (Silicon Dioxide, SiO2 + Fe)
Druzy Quartz (part of a Geode)
Silicon Dioxide (SiO2)
Basalt (River Pebble)
Extrusive mafic igneous rock
Basalt
Basalt (Mafic igneous rock)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with inclusions of Hematite or Magnetite)
Banded Agate (Onyx type)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Porphyritic Basalt (River Rock)
Porphyritic Basalt
Andesite
Andesite (Intermediate Volcanic Rock)
Amethyst
Amethyst (Silicon Dioxide, SiO2)