Man-made Crystal (Lead Glass)
Lead oxide-doped Silica Glass (approx. SiO2 + PbO)
Category
Browse glass specimens identified by the Rock Identifier community.
Man-made Crystal (Lead Glass)
Lead oxide-doped Silica Glass (approx. SiO2 + PbO)
Muscovite Mica (with Quartz matrix)
Muscovite - KAl2(AlSi3O10)(OH)2
Snowflake Obsidian
Obsidian with Cristobalite inclusions (70-75% SiO2)
Goldstone
Aventurine Glass (Man-made glass with copper inclusions)
Chert (Flint) with Limestone Coating
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) cortex
Opalite
Synthetic glass (SiO2 + metal additions)
Obsidian
Volcanic Glass (SiO2)
Milky quartz (rough quartz fragment)
Quartz, silicon dioxide (SiO₂)
Blue quartz (likely dyed or synthetic-treated quartz beads)
Quartz, silicon dioxide (SiO₂)
Botryoidal quartz (likely milky quartz)
Quartz, silicon dioxide (SiO₂)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Muscovite Schist
KAl2(AlSi3O10)(OH)2 (Muscovite) in Schist Matrix
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
Quartz (Drusy/Crystalline)
Silicon Dioxide (SiO2)
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
Amethyst Quartz fragment
SiO2 (Silicon Dioxide with Iron impurities)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Rhinestone (or glass crystal)
Silicon dioxide (if glass) / Various
Amethyst and Green Aventurine (Tumbled Gemstones set in a wand)
Quartz (SiO2) varieties - Amethyst and Aventurine
Chert (Flint)
Chert (SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Pumice
Pumice (a highly vesicular, silicic volcanic rock)
Green Sea Glass
Amorphous Silica (man-made glass), SiO2 + additive metal oxides
Quartz (Grain)
Silicon Dioxide (SiO2)
Snowflake Obsidian
Obsidian with Spherulitic Cristobalite (SiO2)
Clear quartz crystal (likely)
Quartz, silicon dioxide (SiO₂)
Muscovite (Mica)
Muscovite - KAl2(AlSi3O10)(OH)2
Aventurine Quartz
Silicon Dioxide (SiO2) with Fuchsite inclusions
Milky quartz pebble
Quartz (silicon dioxide, SiO₂)
Muscovite Mica
KAl2(AlSi3O10)(OH)2
Muscovite Mica
Muscovite - KAl2(AlSi3O10)(OH)2
Sea Glass
Amorphous Silicon Dioxide (SiO2)
Slag Glass
Silicon dioxide with impurities
Slag (Industrial Glass Slag)
Amorphous Silica / Ferro-silicate Slag
Quartz (Clear/Milky)
Silicon Dioxide (SiO2)
Quartz (Clear Quartz)
Silicon Dioxide (SiO2)
Quartz (Smoky Quartz)
Silicon Dioxide (SiO2)
Green glass cabochon or tumbled stone
Indeterminate; likely man-made glass, possibly aventurine glass rather than a natural mineral
Blue opalite (often sold as synthetic opal)
Opalite glass; amorphous hydrated silica if natural opal (SiO₂·nH₂O)
Obsidian
Obsidian (volcanic glass; primarily SiO2)