Rounded dark-gray pebble, likely basalt or andesite
Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene, amphibole, and minor olivine
igneous
Category
Igneous Rock (Volcanic Glass)
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
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Basalt
Basalt
igneous
Basalt River Pebble
Basalt (Mafic volcanic rock)
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Scoria (vesicular basalt)
Scoria; mafic volcanic rock composed chiefly of plagioclase, pyroxene, and iron-rich glass
igneous
Tumbled translucent pebble, likely quartz or pale chalcedony
Quartz (SiO₂), possibly microcrystalline chalcedony
mineral
Basalt (Vesicular)
Extrusive mafic igneous rock
igneous
Basalt
Extrusive mafic igneous rock
igneous
Slag (Industrial Byproduct)
Anthropogenic Vitreous Silicate material
igneous
Possible vesicular basalt or scoriaceous volcanic rock
Basaltic scoria; chiefly plagioclase, pyroxene, and olivine with volcanic glass
igneous
Porphyritic Basalt (with Pyrolusite or Iron-oxide staining)
Porphyritic Basalt (Mafic Extrusive)
igneous
Rough Amethyst
Silicon Dioxide (SiO2) with Iron impurities
mineral
Basalt Pebble
Extrusive Igneous Rock
igneous
Polished black stone, likely black obsidian
Obsidian (volcanic glass), primarily silica-rich rhyolitic composition
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt Pebble
Extrusive Igneous Rock
igneous
Basalt
Extrusive igneous rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt
Extrusive igneous rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Basalt
Extrusive igneous rock
igneous
Porphyritic Basalt or Porphyry
Porphyritic Igneous Rock
igneous
Porphyritic Basalt (River Rock)
Porphyritic Basalt
igneous
Basalt Pebble
Aphanitic Igneous Rock
igneous
Vesicular Basalt (Scoria)
Basalt (Vesicular texture)
igneous
Vesicular volcanic rock, likely scoria
Scoria; composition commonly basaltic to andesitic, rich in plagioclase and pyroxene
igneous
Basalt (Vesicular)
Vesicular Basalt
igneous
Basalt with Phenocrysts
Porphyritic Basalt
igneous
Likely basalt or dark mafic rock fragment
Basalt; primarily plagioclase feldspar and pyroxene, commonly with olivine and iron oxides
igneous
Rounded iron-rich pebble
Probably weathered basalt or iron-stained volcanic rock; exact identification requires testing
igneous
Basalt cobble
Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene
igneous
Basalt
Extrusive mafic igneous rock
igneous
Unknown Rock Specimen
igneous
Basalt Pebble
Aphanitic Igneous Rock
igneous
Basalt
Extrusive Igneous Rock
igneous
Vesicular basalt (likely scoriaceous basalt)
Basalt; chiefly plagioclase, clinopyroxene, and Fe–Mg minerals, with possible olivine and iron oxides
igneous
Rounded basalt pebble
Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar, pyroxene, and commonly olivine
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
Basalt River Stone
Basalt (Mafic volcanic rock)
igneous
Basalt River Pebble
Basalt (Mafic Volcanic Rock)
igneous