Obsidian
Volcanic Glass (SiO2)
Category
Browse mineraloid specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (SiO2)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Amber (Black)
Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
Snowflake Obsidian
Volcanic glass containing Spherulitic Cristobalite (SiO2)
Obsidian
Volcanic Glass (70-75% SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Opal
Hydrated Silica (SiO2·nH2O)
Gold Sheen Obsidian
Obsidian (volcanic glass with SiO2 + gas inclusions)
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)
Obsidian
Volcanic Glass (SiO2)
White Precious Opal
Hydrated Silica (SiO2·nH2O)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Black Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Limonite (Yellow Ochre)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Limonite (Yellow Ochre)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
Obsidian
Obsidian (Volcanic Glass)
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
Common Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Limonite (Ironstone)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Limonite (Iron Ore)
Limonite (Hydrated iron oxide - FeO(OH)·nH2O)
Glass
Amorphous Silicon Dioxide (SiO2)
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Opalite
Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)
Amber
Succinite (C10H16O)
Amber
Succinate (Fossilized Tree Resin)
Amber
Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)
Amber
Succinite (organic fossilized resin)
Fulgurite
Lechatelierite (Silica glass), typically SiO2
Black Pearl (Tahitian Type)
Aragonite / Conchiolin composite (CaCO3)
Fulgurite
Luechatelierite (SiO2 glass)
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial Byproduct)
Blue Opal Inlay (Simulated/Lab-created)
Hydrated Amorphous Silica (SiO2·nH2O) with polymer resin
Amber
Succinite
Ambergris
Ambergris (Coprolite-adjacent/Organic secretion)
Amber
Succinates (Organic compound: C10H16O)
Amber
Succinicum (Formula: C10H16O)
Amber
Succinicum (Organic Gemstone - Resinite)
Libyan Desert Glass
Natural Silica Glass (SiO2 with minor iron and titanium)
Amber (specifically Red or Cherry Amber)
Succinite (Resinite); Chemical formula: C10H16O