Basalt
Extrusive Igneous Rock
igneous
Category
Igneous Rock (Volcanic Glass)
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Learn about Igneous Rock (Volcanic Glass) in the encyclopedia
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Basalt Fragment
Extrusive Igneous Rock
igneous
Basalt Pebble
Extrusive Igneous Rock
igneous
Basalt
Extrusive igneous rock
igneous
Basalt
Mafic Igneous Rock
igneous
Tumbled blue-gray stone, likely basalt
Basalt (fine-grained mafic volcanic rock; chiefly plagioclase and pyroxene, commonly with magnetite)
igneous
Carnelian
Carnelian (Silicon Dioxide - SiO2)
mineral
Dark, vesicular volcanic rock (probable basaltic scoria)
Basaltic scoria; mainly plagioclase, clinopyroxene, olivine, and volcanic glass
igneous
Likely polished/tumbled dark mineral or glassy rock fragment
Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian
mineral
Rhyolite with Lithophysae and Iron Oxide
Extrusive igneous rock / Felsic volcanic rock
igneous
Vesicular volcanic rock, likely pumice or scoriaceous rhyolite
Pumice/scoria; predominantly silicate glass with quartz–feldspar minerals
igneous
Weathered granite or granitic gneiss
Granite; primarily quartz, feldspar, and mica
igneous
Basalt with Scoria
Amygdaloidal Basalt / Vesicular Basalt
igneous
Basalt
Basalt (Extrusive Igneous Rock)
igneous
Rhyolite
Rhyolite (Extrusive Igneous Rock)
igneous
Red vesicular volcanic rock, likely scoria
Scoria (vesicular basalt/andesite), composed mainly of plagioclase, pyroxene, and iron-rich glass
igneous
Basalt Pebble
Extrusive mafic igneous rock
igneous
Dark volcanic rock, possibly basalt
Basalt; commonly composed of plagioclase, pyroxene, and minor olivine or magnetite
igneous
Porphyritic Basalt or Porphyritic Andesite
Porphyritic volcanic rock
igneous
Polished/tumbled stone, likely mahogany obsidian
Obsidian, natural volcanic glass (composition typically rhyolitic)
igneous
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
igneous
Amethyst
Crystalline Quartz (SiO2) with iron impurities
mineral
Amethyst-rich vesicular volcanic rock (probable amethyst basalt/scoria)
Quartz (SiO₂) in vesicular basaltic volcanic rock; precise identification requires testing
igneous
Beach Pebble (Basalt / Volcanic Rock)
Aphanitic Igneous Rock / Basalt
igneous
Vesicular Basalt
Extrusive mafic igneous rock
igneous
Basalt (Vesicular)
Basalt (Extrusive Igneous)
igneous
Pumice
Pumice, a highly vesicular volcanic rock composed mainly of rhyolitic or dacitic glass
igneous
Basalt
Aphanitic Mafic Volcanic Rock
igneous
Basalt (Vesicular)
Basalt (Extrusive Volcanic Rock)
igneous
Polished granite cobble
Granite, typically quartz–feldspar–biotite granite
igneous
Vesicular basalt (likely weathered volcanic scoria)
Basalt; chiefly plagioclase, clinopyroxene, olivine, and volcanic glass
igneous
Basalt (River Cobble)
Mafic Igneous Rock (Basalt)
igneous
Basalt Pebble
Basalt (Extrusive Igneous Rock)
igneous
Basalt Pebble
Extrusive igneous rock (Mafic)
igneous
Basalt (River Pebble)
Extrusive mafic igneous rock
igneous
Basalt with Chert/Obsidian blade
Aphanitic Mafic Igneous Rock (Basalt) with Microcrystalline Silica (Chert)
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt Pebble
Extrusive Igneous Rock
igneous
Basalt with Phenocrysts
Extrusive Igneous Rock
igneous
Porphyry
Porphyritic Igneous Rock
igneous
Basalt Pebble
Extrusive Igneous Rock
igneous