Obsidian
Volcanic Glass (Amorphous Silica)
Category
Browse mineral (synthetic glass) specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (Amorphous Silica)
Quartz Pebble
Silicon Dioxide (SiO2)
White Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Agate
Agate (Chalcedony), SiO2
Green Aventurine
Quartzite (variety Aventurine) with Fuchsite inclusions (K(Al,Cr)2(AlSi3O10)(OH)2)
Quartz with Chlorite or Epidote inclusions
Silicon Dioxide (SiO2) with inclusions
Quartz Pebble
Silicon Dioxide (SiO2)
Clear Quartz
Silicon Dioxide (SiO2)
Milky Quartz with Iron Inclusions
Quartz (Silicon Dioxide, SiO2)
Milky Quartz Cobble
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz Crystal
Silicon Dioxide (SiO2)
Sandstone
Arenite (SiO2 primarily)
Sandstone with Concretions / Liesegang Rings
Arenite with iron oxide banding
Pale green translucent mineral fragment
Indeterminate; possibly fluorite, calcite, or glassy quartz
Milky quartz with dark host-rock inclusions
Quartz (SiO₂), likely in a granitic or metamorphic matrix
Tumbled green aventurine
Quartzite dominated by quartz (SiO₂), with green mica/fuchsite inclusions
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions (K(Al,Cr)2AlSi3O10(OH)2)
Likely weathered quartz-bearing rock (uncertain identification)
Possibly quartz-rich granite or granitic aplite; exact identification requires a clearer, larger image and tests
Amethyst
Quartz (SiO2)
Jasper (or possibly Agate/Chalcedony) beads
SiO2 (Silicon Dioxide)
Likely calcite or quartz fragment
Uncertain from image; calcite (CaCO₃) is the leading possibility, with quartz (SiO₂) another possibility
Quartz Pebble
Silicon Dioxide (SiO2)
Chert (with Limestone and Iron Oxide staining)
Cryptocrystalline Quartz (SiO2)
Libyan Desert Glass
Impact-melt silica glass (SiO2 + traces of Al, Fe, Ti)
Sandstone (likely Arkose or Lithic)
Clastic sedimentary rock (SiO2 + impurities)
Sandstone (Ferruginous)
Arenite with Iron Oxides
Milky Quartz (Micro-specimen)
Silicon Dioxide (SiO2)
Milky Quartz with Mica Matrix
SiO2 (Silicon Dioxide) with Muscovite/Biotite mica
Likely quartz cluster with iron staining
Quartz (SiO₂), possibly with calcite or feldspar inclusions
Tumbled amethyst
Quartz, purple variety; silicon dioxide (SiO₂), colored mainly by iron impurities and irradiation
Smoky quartz (rough, water-worn crystal)
Quartz, silicon dioxide (SiO₂), smoky variety
Agate Slices and Clear Quartz Points
Agate (SiO2 Chalcedony) and Clear Quartz (SiO2 Crystalline)
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
Quartz (Smoky or Impure Variety)
Silicon Dioxide (SiO2)
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions) - SiO2
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
Quartz
Silicon Dioxide (SiO2)
Blue Aura Quartz
Silicon Dioxide (SiO2) with metallic vapor coating
Quartz Pebble
Silicon Dioxide (SiO2)