Obsidian
Obsidian (volcanic glass), amorphous SiO2 + impurities
Category
Browse manufactured glass specimens identified by the Rock Identifier community.
Obsidian
Obsidian (volcanic glass), amorphous SiO2 + impurities
Obsidian
Obsidian (Amorphous Volcanic Glass, SiO2)
Ferrous Slag
Iron/Steel Slag (Complex Calcium-Alumino-Silicates)
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Pumice
Pumice (Vitreous pyroclastic rock)
Opalite (Synthetic Moonstone/Sea Opal)
Silicon Dioxide (SiO2) glass with metallic inclusions
Quartz (Druzy)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz Pebble (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
Sandstone with Concretions / Liesegang Rings
Arenite with iron oxide banding
Quartz Geode (Water-worn)
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxides
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Pumice
Vesicular volcanic glass (primarily Alumino-silicates)
Pumice
Pumicite
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
Libyan Desert Glass
Tektite (high-silica impact glass), SiO2
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Hematite/Magnetite inclusions)
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Chert (and Flint)
Chert (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Granite Cobble
Felsic intrusive igneous rock
White Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Chert (Jasper variation)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz with Chlorite/Mica inclusions
Silicon Dioxide (SiO2) with phyllosilicate inclusions
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Quartz (Druzy)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Yellow Quartzite
Quartzite (SiO2)
Chert / Jasper
Silicon Dioxide (SiO₂)
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
Crystal Quartz Beads (likely Clear Quartz)
Quartz (SiO₂)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide, SiO2)
Milky Quartz with Iron Staining
Silicon Dioxide (SiO2)
Ferro-silicate Slag
Industrial Vitrified Slag (High-silica amorphous glass)
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
Quartz (Common Quartz Pebble)
Silicon Dioxide (SiO2)
Quartz / Milky Quartz
Silicon Dioxide (SiO2)