Black Obsidian
Volcanic Glass (SiO2)
Category
Browse mineralogical specimens identified by the Rock Identifier community.
Black Obsidian
Volcanic Glass (SiO2)
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
Obsidian
Obsidian (volcanic glass; primarily SiO2)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Obsidian
Volcanic glass (high silica volcanic rock)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Glass
Amorphous Silicon Dioxide (SiO2)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2
Limonite (Iron Ore Congcretion)
Limonite (a mixture of hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)
Tumbled mahogany obsidian
Volcanic glass; primarily SiO₂ with iron-oxide-rich brown inclusions
Opalite
Synthetic Glass (Silica-based)
Black Obsidian
Amorphous volcanic glass (SiO2)
Obsidian (specifically Mahogany Obsidian)
Volcanic glass (high silica content, SiO2)
Obsidian with Mahogany Phasing
Volcanic Glass (SiO2 + Fe2O3)
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Limonite (Iron Stone/Goethite)
Limonite (mixture of hydrated iron oxides, primarily Goethite: α-FeO(OH))
Probable amber fragment
Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)
Amber (Copal)
Succinate (Fossilized Tree Resin)
Common Green Opal
Amorphous Hydrous Silica (SiO2·nH2O)
Black Opal (Kalimaya)
Hydrated Silica (SiO2·nH2O)
Opal
Hydrated silica (SiO2 · nH2O)
Amber
Succinates
Pink Opal
Hydrated Silicon Dioxide (SiO2 · nH2O)
Amber (Tumbled/Polished)
Succinite (Fossilized Tree Resin)
Amber
Succinite (C10H16O)
Amber
Succinate (Fossilized Tree Resin)
Tektite (Indochinite)
Tektite (High-silica natural glass)
Tektite (Indochinite)
Tektite (High-silica natural glass)
Amber
Succinate (Fossilized Tree Resin)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Amber
Succinite (fossilized tree resin)
Opalite
Synthetic glass (SiO2 + metal additions)
Bumblebee Jasper
Anhydrite-Aragonite mixture with Orpiment and Realgar
Amber
Succinates (C10H16O)