Obsidian
Volcanic glass (high silica volcanic rock)
Category
Browse organic mineraloid and mineral specimens identified by the Rock Identifier community.
Obsidian
Volcanic glass (high silica volcanic rock)
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Probable amber fragment
Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)
Polished black obsidian pyramid/block
Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions (70–75% SiO2)
Amber
Succinite (fossilized resin)
Amber
Succinite
Amber
Succinite
Amber
Succinite (specifically for Baltic amber; general formula C10H16O)
Amber
Succinite (Formula: C10H16O)
Amber
Succinite
Amber
Succinite (a specific high-quality amber from the Baltic)
Pearl (Cultured or Natural)
Aragonite (CaCO3) with Conchiolin
Amber
Succinite (formula varies, primarily C10H16O)
Amber
Succinite (Fossilized Resin C10H16O)
Pearl (Imitation or Cultured)
Calcium Carbonate (Aragonite/Calcite) - CaCO3
White Opal
Hydrated Silica (SiO2·nH2O)
Black obsidian
Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)
Black Obsidian
Amorphous volcanic glass (SiO2)
Obsidian (specifically Mahogany Obsidian)
Volcanic glass (high silica content, SiO2)
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)
Limonite (Ironstone Concretion)
Limonite (Hydrated iron(III) oxide-hydroxide, mixtures of FeO(OH)·nH2O)
Limonitic Iron Ore / Goethite
Hydrated Iron(III) oxide-hydroxide (primarily FeO(OH)·nH2O)
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3 with Carotenoid pigments)
Obsidian (likely black volcanic glass)
Obsidian; predominantly silica-rich rhyolitic volcanic glass (approximately 70– on 80% SiO₂)
Polished black obsidian
Volcanic glass, predominantly rhyolitic silica (SiO₂)
Likely obsidian fragment
Volcanic glass, predominantly silica-rich rhyolitic composition (SiO₂-rich)
Obsidian (likely Apache tear or flaked obsidian)
Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, non-crystalline)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite inclusions)
Gold Sheen Obsidian
Volcanic Glass (SiO2 + impurities)
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite/Magnetite inclusions)
Polished mahogany obsidian (likely)
Volcanic glass; primarily silica-rich rhyolitic glass (SiO₂), with iron oxides
Snowflake Obsidian
Volcanic Glass with Spherulite Inclusions (primarily SiO2)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Obsidian
Obsidian (Volcanic Glass, SiO2)
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)