Basalt
Basalt
Category
Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.
Basalt
Basalt
Apache Tear (Obsidian)
Volcanic Glass (SiO2 + impurities)
Obsidian
Volcanic Glass (SiO2 + impurities)
Obsidian
Volcanic Glass (mostly SiO2)
Basalt
Basalt
Polished orbicular stone, likely granite or diorite
Granite–diorite, composed mainly of feldspar, quartz, and dark amphibole/biotite
Scoria
Vesicular Basalt / Scoria
Basalt
Basalt
Basalt
Basalt
Basalt
Basalt
Basalt
Basalt
Basalt
Basalt (composition predominately plagioclase feldspar and pyroxene)
Basalt
Basalt
Diorite
Diorite (intermediate intrusive igneous rock)
Diorite
Diorite (Intermediate intrusive igneous rock)
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (Druzy)
Silicon Dioxide (SiO2)
Snowflake Obsidian
Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)
Polished red jasper
Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides.
Agate
Silicon Dioxide (Chalcedony), SiO2
Feldspar-rich Granite (Pink Granite)
Granite (Orthoclase rich)
Granite Pebble (River Rock)
Granite (composed primarily of Quartz, Feldspar, and Mica)
Vesicular Basalt with Quartz
Vesicular Basalt (SiO2 inclusions)
Milky Quartz
Silicon Dioxide (SiO2)
Komatiite Drill Core
Ultramafic Volcanic Rock (Spinifex Texture)
Basalt River Pebble
Basalt (Aphanitic Mafic Volcanic Rock)
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
Amygdaloidal Rhyolite
Amygdaloidal Rhyolite (Felsic volcanic rock)
Banded Rhyolite
Rhyolite (High-silica volcanic rock)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic Volcanic Rock)
Porphyritic Rhyolite (Red Porphyry)
Porphyritic Rhyolite (Felsic volcanic rock)
Basalt
Basalt (Aphanitic Mafic Volcanic Rock)
Porphyritic Rhyolite (Red Porp)
Porphyritic Rhyolite (Felsic volcanic rock)
Basalt River Pebble
Extrusive mafic igneous rock; primarily composed of Plagioclase Feldspar and Pyroxene
Chalcedony (Common Opal or Agate variant)
Silicon Dioxide (SiO₂)
Basalt (Road Gravel)
Aphanitic mafic volcanic rock (various compositions of plagioclase feldspar and pyroxene)
Quartz (Agate/Chalcedony)
Silicon Dioxide (SiO2)
Weathered, iron-stained rhyolite pebble (possibly rhyolitic volcanic breccia)
Rhyolite, a felsic volcanic rock; mainly quartz and alkali feldspar with minor plagioclase, altered mafic minerals, and iron-oxide staining
Basalt
Basalt
Pumice
Pumice (Volcanic Glass Foam)
Dalmatian Jasper
Peralkaline Quartz Feldspar Porphyry