Obsidian (specifically Silver Sheen Obsidian)
Volcanic Glass (approx. 70–75% SiO2 plus MgO, Fe3O4)
Category
Browse mineral and glass specimens identified by the Rock Identifier community.
Obsidian (specifically Silver Sheen Obsidian)
Volcanic Glass (approx. 70–75% SiO2 plus MgO, Fe3O4)
Lepidolite in Quartz (Lithium-bearing Ore)
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2) and Quartz (SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Sandstone (Pebble/Cobble)
Arenite (primarily SiO2)
Chert (Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Chert (Flint variety)
Microcrystalline context of Quartz (SiO2)
Jasper (likely Ocean Jasper or Variegated Jasper)
Silicon Dioxide (SiO2) with impurities
Epidote (likely Pistacite in Epidosite rock)
Epidote: Ca2(Al,Fe)3(SiO4)3(OH)
Common Green Opal
Hydrated amorphous silicon dioxide (SiO2·nH2O)
Blue Quartzite
Quartzite (primarily SiO2 with inclusions)
Jasper
Silicon dioxide (SiO2)
Citrine
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Sapphire
Corundum (Al2O3)
Druzy Quartz on Matrix
Silicon Dioxide (SiO2)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Bloodstone (Heliotrope)
Silicon Dioxide (SiO2) - Variety of Chalcedony/Jasper
Blue Chalcedony
Silicon Dioxide (SiO2)
Dumortierite Quartz (Blue Quartz)
Al7(BO3)(SiO4)3O3 / Quarz with Dumortierite inclusions
Black Onyx
Silicon Dioxide (SiO2)
Milky Quartz (polished heart)
Quartz (Silicon Dioxide, SiO2)
Blue Agate (Tumbled and Dyed)
Silicon Dioxide (SiO2) with likely organic dyes
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Chert (Arrowhead Preform or Flake)
Microcrystalline Quartz (SiO2)
Red Jasper
Jasper (Silicon Dioxide, SiO2 with Iron Oxide impurities)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Breciated Chert
Brecciated Chert (Microcrystalline Quartz, SiO2)
Rose Quartz
Quartz (Silicon Dioxide - SiO2)
Green Druzy Quartz (Prasiolite)
Silicon Dioxide (SiO2) with inclusions (typically Chlorite or Actinolite)
Green Aventurine
Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2(AlSi3O10)(OH)2)
Rhodonite with Manganese Oxides
Rhodonite (Mn,Fe,Mg,Ca)SiO3
Amethyst
Silicon Dioxide (SiO2) with trace Iron (Fe) impurities
Peridot
Olivine ((Mg, Fe)2SiO4)
Glass Nugget (Tumbled Glass)
Amorphous Silicon Dioxide (SiO2) with additives
Red Jasper
Red Jasper (SiO2 with Fe2O3 impurities)
Red Sandstone
Arenite (Ferruginous Sandstone)
Quartz Pebble (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
Jasper (Iron-stained Chert)
Silicon Dioxide (SiO2) with impurities of Hematite or Goethite
Psilomelane (Black Hematite/Manganese Ore)
Barium Manganese Oxide (Formula: BaMn9O18(OH)4)