Rock Identifier

Category

Organic Crystal (Mineraloid)

Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.

Cullet Glass (Slag) (Amorphous Silicon Dioxide (Man-made)) — Mineraloid

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

Snowflake Obsidian (Spherulitic Volcanic Glass (primarily SiO2)) — igneous

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2)

Opal (Hydrated silica (SiO2 · nH2O)) — mineraloid

Opal

Hydrated silica (SiO2 · nH2O)

Fire Opal (in matrix) (Hydrated Silica (SiO2·nH2O)) — Mineraloid

Fire Opal (in matrix)

Hydrated Silica (SiO2·nH2O)

Limonite (Yellow Ochre) (Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)) — mineral

Limonite (Yellow Ochre)

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Limonite (Yellow Ochre) (Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)) — mineral

Limonite (Yellow Ochre)

Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)

Limonite (Yellow Ochre) (Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)) — mineral

Limonite (Yellow Ochre)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Slag (Industrial Glass) (Anthropogenic Amorphous Vitreous Silicate) — mineraloid

Slag (Industrial Glass)

Anthropogenic Amorphous Vitreous Silicate

Ethiopian Opal (Welo Opal) (Hydrated Amorphous Silica (SiO2·nH2O)) — mineraloid

Ethiopian Opal (Welo Opal)

Hydrated Amorphous Silica (SiO2·nH2O)

Bumblebee Jasper (Anhydrite-Aragonite mixture with Orpiment and Realgar) — mineraloid

Bumblebee Jasper

Anhydrite-Aragonite mixture with Orpiment and Realgar

Libyan Desert Glass (Natural Silica Glass (SiO2 with minor iron and titanium)) — mineraloid

Libyan Desert Glass

Natural Silica Glass (SiO2 with minor iron and titanium)

Obsidian (Volcanic glass) — igneous

Obsidian

Volcanic glass

Black Obsidian (Volcanic glass (Amorphous silicates)) — igneous

Black Obsidian

Volcanic glass (Amorphous silicates)

Opalite (Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)) — mineraloid

Opalite

Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)

Pearl (Aragonite / Calcium Carbonate (CaCO3)) — mineraloid

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Cullet Glass (Slag Glass) (Amorphous Silicon Dioxide (Industrial Byproduct)) — mineraloid

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial Byproduct)

Precious Opal (Hydrated Silica (SiO2·nH2O)) — mineraloid

Precious Opal

Hydrated Silica (SiO2·nH2O)

Green Opal (Hydrated Silica (SiO2·nH2O)) — mineraloid

Green Opal

Hydrated Silica (SiO2·nH2O)

Cullet Glass (Slag Glass) (Amorphous Silicon Dioxide (Industrial byproduct)) — mineraloid

Cullet Glass (Slag Glass)

Amorphous Silicon Dioxide (Industrial byproduct)

Fulgurite (Luechatelierite (SiO2 glass)) — mineraloid

Fulgurite

Luechatelierite (SiO2 glass)

Amber (Succinite) — Mineraloid

Amber

Succinite

Burmese Amber (Burmite) (Burmite (C10H16O)) — mineraloid

Burmese Amber (Burmite)

Burmite (C10H16O)

Opal (Hydrated Silica (SiO2·nH2O)) — mineral

Opal

Hydrated Silica (SiO2·nH2O)

Mahogany Obsidian (Volcanic glass (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic glass (SiO2 + Fe2O3)

Common Green Opal (Amorphous Hydrous Silica (SiO2·nH2O)) — mineraloid

Common Green Opal

Amorphous Hydrous Silica (SiO2·nH2O)

Tektite (Indochinite) (Tektite (High-silica natural glass)) — mineraloid

Tektite (Indochinite)

Tektite (High-silica natural glass)

Precious Opal (Hydrated silica (SiO2·nH2O)) — mineraloid

Precious Opal

Hydrated silica (SiO2·nH2O)

Black Opal (Hydrated Silica (SiO2·nH2O)) — Mineraloid

Black Opal

Hydrated Silica (SiO2·nH2O)

Obsidian (Volcanic Glass (70-75% SiO2)) — igneous

Obsidian

Volcanic Glass (70-75% SiO2)

Limonite (Hydrated Iron Oxide / Bog Iron) (FeO(OH)·nH2O) — Mineral (Sedimentary context)

Limonite (Hydrated Iron Oxide / Bog Iron)

FeO(OH)·nH2O

Mineral (Sedimentary context)

Limonite (Iron Ore) (FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)) — mineral

Limonite (Iron Ore)

FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide mixture)

Black Opal (Kalimaya) (Hydrated Silica (SiO2·nH2O)) — mineraloid

Black Opal (Kalimaya)

Hydrated Silica (SiO2·nH2O)

Limonite (Iron Ore) (Limonite (FeO(OH)·nH2O)) — mineral

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Glass (Amorphous Silicon Dioxide (SiO2)) — mineraloid

Glass

Amorphous Silicon Dioxide (SiO2)

Black Obsidian (Volcanic Glass (predominantly SiO2, Silicon Dioxide)) — igneous

Black Obsidian

Volcanic Glass (predominantly SiO2, Silicon Dioxide)

Orange cabochon gemstone, likely amber or amber-like resin (Natural amber: fossilized plant resin (organic mineraloid), commonly succinite; exact identification requires testing) — gemstone

Orange cabochon gemstone, likely amber or amber-like resin

Natural amber: fossilized plant resin (organic mineraloid), commonly succinite; exact identification requires testing

Precious Opal (Hydrated Silica (SiO2·nH2O)) — mineral

Precious Opal

Hydrated Silica (SiO2·nH2O)

Opalite (Synthetic glass (SiO2 + metal additions)) — mineraloid

Opalite

Synthetic glass (SiO2 + metal additions)

Boulder Opal (Hydrated Silica (SiO2·nH2O)) — mineraloid

Boulder Opal

Hydrated Silica (SiO2·nH2O)

Black Obsidian (Volcanic Glass (SiO2)) — igneous

Black Obsidian

Volcanic Glass (SiO2)

Obsidian (Volcanic glass (silica-rich rhyolitic melt; primarily SiO₂)) — igneous

Obsidian

Volcanic glass (silica-rich rhyolitic melt; primarily SiO₂)

Obsidian (Obsidian (Extrusive Volcanic Glass)) — igneous

Obsidian

Obsidian (Extrusive Volcanic Glass)