Rock Identifier

Category

Organic Crystal (Mineraloid)

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

Obsidian (Volcanic Glass (Amorphous SiO2)) — igneous

Obsidian

Volcanic Glass (Amorphous SiO2)

Obsidian (Volcanic glass) — igneous

Obsidian

Volcanic glass

Black Obsidian (Volcanic Glass (SiO2 + impurities like Fe3O4)) — igneous

Black Obsidian

Volcanic Glass (SiO2 + impurities like Fe3O4)

Obsidian (Amorphous volcanic glass (primarily SiO2)) — igneous

Obsidian

Amorphous volcanic glass (primarily SiO2)

Obsidian (Volcanic glass (SiO2 - Silicon Dioxide with impurities)) — igneous

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

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

Precious Opal

Hydrated Silica (SiO2·nH2O)

Mahogany Obsidian (Obsidian (volcanic glass with hematite/magnetite inclusions)) — igneous

Mahogany Obsidian

Obsidian (volcanic glass with hematite/magnetite inclusions)

Limonite (Iron Stone/Ocher) (Limonite (FeO(OH)·nH2O)) — mineral

Limonite (Iron Stone/Ocher)

Limonite (FeO(OH)·nH2O)

Snowflake Obsidian (Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)) — igneous

Snowflake Obsidian

Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)

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

Green Opal

Hydrated amorphous silica (SiO2·nH2O)

Snowflake Obsidian (Volcanic Glass with Cristobalite inclusions (70–75% SiO2)) — Igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite inclusions (70–75% SiO2)

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Limonite/Goethite on Shale (Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock) — sedimentary

Limonite/Goethite on Shale

Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock

Conch Pearl (Calcareous concretion (CaCO3)) — mineraloid

Conch Pearl

Calcareous concretion (CaCO3)

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Mahogany Obsidian (Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)

Obsidian (Volcanic glass (mainly SiO2 with inclusions)) — igneous

Obsidian

Volcanic glass (mainly SiO2 with inclusions)

Amber (Succinite (C10H16O)) — mineraloid

Amber

Succinite (C10H16O)

Fulgurite (Liesegang (Fulgurite)) — Mineraloid

Fulgurite

Liesegang (Fulgurite)

Sea Glass (Frosted Quartz/Glass) (Amorphous Silicon Dioxide (SiO2)) — Mineraloid

Sea Glass (Frosted Quartz/Glass)

Amorphous Silicon Dioxide (SiO2)

White Opal (Hydrated Amorphous Silica (SiO2·nH2O)) — Mineraloid

White Opal

Hydrated Amorphous Silica (SiO2·nH2O)

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

Black Opal

Hydrated silica (SiO2·nH2O)

Dragon's Breath (Mexican Opal Glass) (Artisan Foil Glass (SiO2 based)) — mineraloid

Dragon's Breath (Mexican Opal Glass)

Artisan Foil Glass (SiO2 based)

Sea Glass (often mistaken for Gemstones) (Amorphous Silica (SiO2) with trace additives) — mineraloid

Sea Glass (often mistaken for Gemstones)

Amorphous Silica (SiO2) with trace additives

Common Opal (SiO2·nH2O (Hydrated Silicon Dioxide)) — mineraloid

Common Opal

SiO2·nH2O (Hydrated Silicon Dioxide)

Snowflake Obsidian (Volcanic Glass with Cristobalite Inclusions) — igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite Inclusions

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

Limonite (Iron Ore)

Limonite (Hydrated iron oxide - FeO(OH)·nH2O)

Common Opal (Hydrated Amorphous Silica (SiO2·nH2O)) — mineraloid

Common Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Obsidian (Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)) — igneous

Obsidian

Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)

Common Opal in Host Rock (Hydrated Silica (SiO2·nH2O)) — mineraloid

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

Cobalt Blue Slag Glass (Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives) — mineraloid

Cobalt Blue Slag Glass

Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives

Limonite/Goethite Concretion (Hydrated Iron(III) Oxide-hydroxide (FeO(OH)·nH2O)) — sedimentary

Limonite/Goethite Concretion

Hydrated Iron(III) Oxide-hydroxide (FeO(OH)·nH2O)

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

Limonite (Ironstone)

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

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

Green Opal or Yellow Opal

Hydrated Silica (SiO2·nH2O)

Opalite (Synthetic Glass (Amorphized Silicon Dioxide)) — mineraloid

Opalite

Synthetic Glass (Amorphized Silicon Dioxide)

Tektite (Indochinite) (Tektite (SiO2 + Al2O3)) — mineraloid

Tektite (Indochinite)

Tektite (SiO2 + Al2O3)

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

Opal

Hydrated silica (SiO2·nH2O)

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

Opal

Hydrated Silica (SiO2·nH2O)

Black Obsidian (Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)) — igneous

Black Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

Limonite (Iron Ore) (Limonite (Hydrous ferric oxides), generic formula FeO(OH)·nH2O) — mineral

Limonite (Iron Ore)

Limonite (Hydrous ferric oxides), generic formula FeO(OH)·nH2O

Amber (Succinite (approximate formula C10H16O)) — mineraloid

Amber

Succinite (approximate formula C10H16O)

Amber (specifically Burmese Amber or Burmite) (Succiniferous fossil resin (C10H16O)) — mineraloid

Amber (specifically Burmese Amber or Burmite)

Succiniferous fossil resin (C10H16O)