Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in Rhyolitic Matrix
Category
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in Rhyolitic Matrix
Basalt
Extrusive mafic igneous rock
Rhyolite
Rhyolite (Extrusive Igneous Rock)
Basalt Cobble
Aphanitic Mafic Igneous Rock (Basalt)
Vesicular Basalt (River Rock)
Afanitic Vesicular Basalt
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Basalt
Basalt (Mafic volcanic rock)
Basalt
Basalt (Mafic volcanic rock)
Basalt
Extrusive mafic igneous rock
Basalt (Polished Pebble)
Basalt (Mafic volcanic rock)
Quartz Veined Basalt
Mafic Volcanic Rock with Microcrystalline Quartz (SiO2)
Bumblebee Jasper
Volcanic Tuff (mixture of Quartz, Sulfur, Hematite, and Orpiment)
Blue Chalcedony (likely dyed Agate)
Silicon Dioxide (SiO₂)
Vesicular Basalt (or Scoria)
Vesicular Basalt (Aphanitic-vesicular volcanic rock)
Vesicular Basalt with Amygdaloidal Infill
Basalt (Mafic Extrusive Igneous Rock)
Basalt (Vesicular)
Basalt (Extrusive Mafic Igneous Rock)
Basalt
Basalt (Aphanitic Mafic Igneous Rock)
Basalt
Extrusive mafic igneous rock
Peridotite (with Olivine)
Peridotite (rich in Olivine, (Mg,Fe)2SiO4)
Basalt
Basalt (Mafic Extrusive)
Yellow Agate
Chalcedony (cryptocrystalline Quartz), SiO2
Flower Agate
Chalcedony (Silicon Dioxide) with Plume Inclusions, SiO2
Basalt
Basalt (Aphanitic-fine grained mafic igneous rock)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
Vesicular Basalt
Extrusive Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Basalt
Basalt (Igneous Volcanic Rock)
Porphyritic Rhyolite
Rhyolite (Porphyritic texture)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Basalt River Pebble
Mafic volcanic rock (Basalt)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)
Basalt
Mafic Igneous Rock
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Porphyritic Rhyolite (Birdseye Rhyolite)
Rhyolite (Porphyritic texture)
Olivine/Peridot
Magnesium Iron Silicate (Mg,Fe)2SiO4
Basalt River Stone
Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
Basalt Pebble
Basalt (Aphanitic Mafic Igneous Rock)
Basalt (Purple-tinted scoria/vesicular variety)
Extrusive mafic igneous rock (SiO2 range 45–52%)
Pumice or Scoria
Vesicular volcanic rock
Dalmation Jasper (Dalmation Stone)
Perthitic feldspar-quartz-amphibole rock
Basalt
Basalt (composition of plagioclase, pyroxene, and olivine)
Basalt with Vesicular Texture
Basalt (SiO2 range 45-52%)