Obsidian
Volcanic Glass (SiO2)
Category
Browse glass specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Perlite (Unexpanded)
Amorphous volcanic glass
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (SiO2)
Black Obsidian
Volcanic Glass (SiO2)
Black Obsidian
Obsidian (Volcanic Glass)
Pumice
Pumice (Volcanic Glass)
Obsidian with Matrix
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Pumice
Pumice (volcanic glass)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Obsidian (volcanic glass)
Obsidian
Volcanic Glass (SiO2)
Pumice
Vesicular volcanic glass
Pumice
Vesicular volcanic glass
Obsidian
Obsidian (volcanic glass)
Black tumbled stone, possibly obsidian
Obsidian (volcanic glass; predominantly SiO₂), identification uncertain from image
Small pale mineral fragment, likely quartz or calcite
Quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing
Rounded pebble, likely quartz-rich sandstone or chert
Indeterminate lithic clast; possibly quartz arenite or microcrystalline quartz (SiO₂)
Muscovite Mica (Granitic Pegmatite)
Muscovite - KAl2(AlSi3O10)(OH)2
Quartz Pebble (Iron-Stained)
Quartz (Silicon Dioxide - SiO2)
Amethyst
Silicon Dioxide (SiO2 with iron impurities)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Quartz Pebble (Chert/Chalcedony)
Silicon Dioxide (SiO2)
Quartz (Smoky or Clear variety with inclusions)
Silicon Dioxide (SiO2)
Gem-set gold ring
Gold alloy setting with a colorless faceted gemstone, possibly quartz or glass; the stone cannot be identified reliably from the image
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2
Pumice
Pumice (Vesicular Felsic Igneous Rock)
Blue crystal pendant (likely blue glass or synthetic crystal)
Not identifiable from the image; possibly synthetic quartz or glass, rather than a natural mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Obsidian (likely black volcanic glass)
Obsidian; primarily amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
Amethyst (likely tumbled or cut fragment)
Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation
Tumbled amethyst
Quartz, purple variety; silicon dioxide (SiO₂), colored mainly by iron impurities and irradiation
Quartz crystal fragment (likely milky quartz)
Quartz, silicon dioxide (SiO₂)
Tumbled amethyst
Quartz, purple variety; SiO₂