Glass
Amorphous Silicon Dioxide (SiO2)
Category
Browse organic mineraloid specimens identified by the Rock Identifier community.
Glass
Amorphous Silicon Dioxide (SiO2)
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Opalite
Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)
Amber
Succinite
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial Byproduct)
Blue Opal Inlay (Simulated/Lab-created)
Hydrated Amorphous Silica (SiO2·nH2O) with polymer resin
Fulgurite
Lechatelierite (Silica glass), typically SiO2
Black Pearl (Tahitian Type)
Aragonite / Conchiolin composite (CaCO3)
Fulgurite
Luechatelierite (SiO2 glass)
Libyan Desert Glass
Natural Silica Glass (SiO2 with minor iron and titanium)
Cullet (Slag Glass)
Amorphous Silica (Industrial byproduct)
Tektite (Indochinite)
Tektite - High-silica amorphous glass (SiO2 + Al2O3)
Tektite (Indochinite)
Tektite (High-silica impact glass)
Black Opal
Hydrated Silica (SiO2·nH2O)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Cullet Glass (Man-made Glass Slag)
Amorphous Silica (SiO2) with chemical additives
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Obsidian
Obsidian (volcanic glass; primarily SiO2)
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Obsidian
Volcanic glass (high silica volcanic rock)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Obsidian
Obsidian (Volcanic Glass), primarily SiO2
Limonite (Iron Ore Congcretion)
Limonite (a mixture of hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Fire Opal (in Matrix)
Hydrated Silica (SiO2·nH2O)
Cobalt Glass Slug (Man-made Glass)
Amorphous Silica with Cobalt Oxide (SiO2 + CoO)
Opalite
Synthetic Glass (Amorphized Silicon Dioxide)
Common Opal (Green Opal / Pistachio Opal)
Hydrated silica (SiO2·nH2O)
Slag (Industrial Glass)
Anthropogenic Amorphous Vitreous Silicate
Pearl
Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin
Conch Pearl
Calcareous concretion (CaCO3)
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Sea Glass (Frosted Quartz/Glass)
Amorphous Silicon Dioxide (SiO2)
Amber
Succinite (approximate formula C10H16O)
Black Opal
Hydrated silica (SiO2·nH2O)
Amber
Succinite (C10H16O)
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Opal
Hydrated silica (SiO2·nH2O)
Fulgurite
Liesegang (Fulgurite)