Pumice
Pumice (Amorphous volcanic glass)
Category
Browse synthetic glass specimens identified by the Rock Identifier community.
Pumice
Pumice (Amorphous volcanic glass)
Pumice
Pumice
Pumice
Vesicular Felsic Extrusive Igneous Rock
Red Tuff / Sandstone
Rhyolitic Tuff / Pyroclastic Volcanic Rock
Fulgurite
Fulgurite (Lechatelierite)
Snowflake Obsidian
Spherulitic Obsidian (Volcanic glass containing Cristobalite)
Pumice
Pumice (a highly vesicular extrusive volcanic glass)
Pumice
Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)
Pumice
Pumice (Amorphous volcanic glass)
Fulgurite
Fulgurite (Lechatelierite-rich variety)
Obsidian
Volcanic Glass (SiO2 rich)
Snowflake Obsidian
Vitreous Volcanic Rock (Amorphous Silicate), SiO2
Jasper
Chalcedony (SiO2)
Pumice
Pumice (Amorphous volcanic glass)
Quartz
Silicon Dioxide (SiO2)
Pumice
Pumice (Volcanic Rock / Glass Froth)
Snowflake Obsidian
Volcanic Glass with Spherulite inclusions (SiO2)
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Obsidian
Volcanic Glass (High silica amorphous rock)
Pumice (Volcanic Rock)
Vesicular volcanic rock (composed largely of amorphous volcanic glass)
Pumice
Pumice (Vesicular Rhyolite/Andesite)
Obsidian
Volcanic Glass (Amorphous Silica, SiO2)
Snowflake Obsidian
Obsidian with Cristobalite inclusions (SiO2)
Black Obsidian
Amorphous volcanic glass (SiO2 + impurities)
Obsidian
Obsidian (Volcanic Glass, ~70% SiO2)
Tumbled brown chalcedony or jasper
Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper
Polished black obsidian pyramid/block
Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)
Polished agate/chalcedony fragment
Microcrystalline quartz (SiO₂), likely banded chalcedony or agate
White Topaz
Al2SiO4(F,OH)2
Quartz (Pale Rose or Milky Variety)
Silicon Dioxide (SiO2)
Quartzite Pebble
Metamorphic rock predominantly composed of Quartz (SiO2)
Tektite (Indochinite)
Tektite (Natural silica glass)
Slag (Industrial Glass)
Artificial Vitreous Silicate
Pumice
Pumice (volcanic glass rock)
Goldstone (aventurine glass)
Man-made copper-bearing glass; not a natural mineral (commonly sold as blue/brown goldstone)
Black Obsidian
Volcanic Glass (predominantly SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Tektite (Indochinite)
Tektite - High-silica amorphous glass (SiO2 + Al2O3)
Possible iron-rich chert or slag-like rock
Microcrystalline quartz (SiO₂), possibly iron-stained chert; exact identification is uncertain from the image
Red Quartzite
Quartzite (SiO2)
Pumice
Pumice (Amorphous volcanic glass)
Pumice
Pumice (Amorphous volcanic glass)