Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Category
Browse mineral (or mineraloid if microcrystalline) specimens identified by the Rock Identifier community.
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Limonite (with Pyrite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Obsidian
Volcanic Glass (SiO2 rich)
Obsidian (Gold Sheen)
Obsidian (SiO2 + impurities)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
Obsidian
Volcanic Glass (SiO2 + impurities)
Snowflake Obsidian (Flower Jasper variant)
Vitreous volcanic silicate with cristobalite inclusions
Mahogany Obsidian
Volcanic Glass (Silicate: SiO2 + Fe2O3)
Mahogany Obsidian
Volcanic glass containing Magnetite/Hematite
Limonite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Obsidian
Volcanic Glass (predominantly SiO2)
Amber
Succinite (with a generalized formula of C10H16O)
Yellow Ocher (Limonite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite or Magnetite inclusions)
Obsidian
Volcanic Glass (Silicon Dioxide with impurities)
Obsidian
Volcanic Glass (Amorphous Silica)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Common Opal with Host Rock
Opal (Hydrated silica, SiO2·nH2O)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Amber
Succinite (Organic Mineraloid) - C10H16O
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Opal
Hydrated silica (SiO2·nH2O)
Limonite (Yellow Ochre)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Mahogany Obsidian
Obsidian (volcanic glass with hematite/magnetite inclusions)
White Precious Opal
Hydrated Silica (SiO2·nH2O)
Amber
Succinite (organic fossilized resin)
Pearls
Aragonite (calcium carbonate) and Conchiolin
Precious Opal
Hydrated Silica (SiO2·nH2O)
Amber
Succinite (organic hydrocarbon)
Amber
Succinite (C10H16O)
Amber
Succinite (specifically for Baltic amber); approximate formula C10H16O
Amber
Succinite (C10H16O)
Mahogany Obsidian
Obsidian (SiO2 + Fe2O3)
Snowflake Obsidian
Spherulitic Volcanic Glass (SiO2 + impurities)