Obsidian
Amorphous volcanic glass (primarily SiO2)
Category
Browse volcanic glass (igneous) specimens identified by the Rock Identifier community.
Obsidian
Amorphous volcanic glass (primarily SiO2)
Obsidian
Obsidian (Amorphous Volcanic Glass, SiO2)
Obsidian (Apache Tear)
Volcanic Glass (composed mainly of SiO2)
Smoky Quartz (Apache Tear Variety)
Silicon dioxide (SiO2) - Volcanic Glass
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Snowflake Obsidian
Volcanic glass containing Spherulites (SiO2)
Snowflake Obsidian
Volcanic glass containing Cristobalite (SiO2)
Apache Tear
Obsidian (Hydrated Volcanic Glass - SiO2)
Basalt with vesicles/amygdules
Basalt (containing volcanic glass and plagioclase)
Pumice
Pumice (a highly vesicular volcanic glass)
Pumice
Pumice (a highly vesicular volcanic glass)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Snowflake Obsidian
Obsidian (volcanic glass) with Cristobalite inclusions
Black Obsidian with white veins
Volcanic Glass (70–75% SiO2)
Obsidian
Obsidian (Volcanic Glass, ~70% SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Pumice
Pumice (volcanic glass with vesicular texture)
Obsidian Arrowhead
Volcanic Glass (Primary composition: SiO2)
Pumice
Pumice (Volcanic Rock / Glass Froth)
Polished Black Onyx (or Obsidian)
Silicon Dioxide (SiO2)
Tumbled purple jasper (likely rhyolite-derived jasper)
Microcrystalline quartz (SiO₂) with iron/manganese oxide impurities; possibly purple rhyolitic jasper
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Obsidian (Black Obsidian)
Amorphous volcanic glass (primarily SiO2)
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide, SiO2)
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite or Magnetite inclusions)
Obsidian
Volcanic Glass (70-75% SiO2)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Snowflake Obsidian
Vitreous volcanic rock with Cristobalite inclusions (mostly SiO2)
Volcanic scoria (likely)
Scoria, a vesicular basaltic to andesitic volcanic rock
Tumbled obsidian
Volcanic glass; chiefly silica-rich rhyolitic glass (approximately 70–80% SiO₂)
Chalcedony (Dyed Agate and Citrine-style Quartz)
Silicon Dioxide (SiO2)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Snowflake Obsidian (possibly mixed with Jasper or other matrix)
Obsidian with Cristobalite inclusions
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Tumbled Stones Collection (Tiger's Eye, Snowflake Obsidian, Aventurine, etc.)
Silica minerals (primarily SiO2)
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
Snowflake Obsidian
Spherulitic Obsidian (Volcanic glass containing Cristobalite)
Vesicular basalt (probable scoriaceous basalt)
Basalt; chiefly plagioclase, clinopyroxene, and iron-titanium oxides, with possible olivine
Obsidian
Vitreous volcanic silicate (70-75% SiO2)
Red vesicular volcanic rock, likely scoria
Basaltic scoria; predominantly plagioclase, pyroxene, olivine, and volcanic glass