Obsidian
Volcanic Glass (70-75% SiO2)
Category
Browse sedimentary (or mineraloid) specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (70-75% SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Gold Sheen Obsidian
Obsidian (volcanic glass with SiO2 + gas inclusions)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Obsidian (likely black obsidian)
Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)
Gold Sheen Obsidian
Volcanic Glass (SiO2 + impurities)
Obsidian (likely black obsidian)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
Amber
Succinite
Obsidian
Amorphous volcanic glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Volcanic Glass with Spherulite Inclusions (70-75% SiO2)
Obsidian (black volcanic glass)
Obsidian; predominantly silica-rich volcanic glass, commonly rhyolitic (approximately 70–75% SiO₂)
Tumbled black obsidian (likely)
Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, amorphous)
Obsidian (likely black volcanic glass)
Obsidian; silica-rich, noncrystalline volcanic glass, typically rhyolitic (approximately 70–75% SiO₂)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions
Black Obsidian
Volcanic Glass (SiO2 + MgO / Fe3O4)
Black Obsidian
Volcanic Glass (SiO2)
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
Obsidian
Obsidian (volcanic glass; primarily SiO2)
Obsidian
Volcanic glass (high silica volcanic rock)
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2
Fire Opal (in Matrix)
Hydrated Silica (SiO2·nH2O)
Black obsidian
Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)
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)
Tumbled mahogany obsidian
Volcanic glass; primarily SiO₂ with iron-oxide-rich brown inclusions
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Amber
Succinite (with formula approximately C10H16O)
Amber
Succinite