Rock Identifier

Category

Organic Crystal (Mineraloid)

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

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

Opal (Precious Opal)

Hydrated Silica (SiO2·nH2O)

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Limonite (Ironstone) (Limonite (mixture of hydrated iron oxides, primarily Goethite α-FeO(OH))) — mineral

Limonite (Ironstone)

Limonite (mixture of hydrated iron oxides, primarily Goethite α-FeO(OH))

Obsidian (Gold Sheen) (Obsidian (SiO2 + impurities)) — igneous

Obsidian (Gold Sheen)

Obsidian (SiO2 + impurities)

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

White Opal

Hydrated Silica (SiO2·nH2O)

Snowflake Obsidian (Volcanic Glass with Spherulite Inclusions (70-75% SiO2)) — igneous

Snowflake Obsidian

Volcanic Glass with Spherulite Inclusions (70-75% SiO2)

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 (SiO2 - Silicon Dioxide with impurities)) — igneous

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Obsidian (Volcanic Glass (Amorphous SiO2)) — igneous

Obsidian

Volcanic Glass (Amorphous SiO2)

Obsidian (Obsidian) — igneous

Obsidian

Obsidian

Obsidian (Volcanic Glass (SiO2 rich)) — igneous

Obsidian

Volcanic Glass (SiO2 rich)

Limonite (Iron Ore) (Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)) — Mineral

Limonite (Iron Ore)

Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)

Mahogany Obsidian (Volcanic glass (Silicon Dioxide with Hematite/Magnetite inclusions)) — igneous

Mahogany Obsidian

Volcanic glass (Silicon Dioxide with Hematite/Magnetite inclusions)

Fire Opal (in Matrix) (Hydrated Silica (SiO2·nH2O)) — mineral

Fire Opal (in Matrix)

Hydrated Silica (SiO2·nH2O)

Obsidian (Volcanic Glass (Amorphous Silicon Dioxide)) — igneous

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Obsidian (Volcanic Glass (70% or more SiO2)) — igneous

Obsidian

Volcanic Glass (70% or more SiO2)

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

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Limonite (Iron Ore) (Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)) — mineral

Limonite (Iron Ore)

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

Snowflake Obsidian (Obsidian with Spherulitic Cristobalite (SiO2)) — igneous

Snowflake Obsidian

Obsidian with Spherulitic Cristobalite (SiO2)

Obsidian (Obsidian (Amorphous volcanic glass, predominantly SiO2)) — igneous

Obsidian

Obsidian (Amorphous volcanic glass, predominantly SiO2)

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

Mahogany Obsidian

Obsidian (SiO2 + Fe2O3)

Amber (Succinite (fossilized tree resin)) — mineraloid / sedimentary organic material

Amber

Succinite (fossilized tree resin)

mineraloid / sedimentary organic material

Tumbled black stone, likely black obsidian (Obsidian — natural volcanic glass, primarily SiO₂) — igneous

Tumbled black stone, likely black obsidian

Obsidian — natural volcanic glass, primarily SiO₂

Obsidian (Volcanic Glass (SiO2)) — igneous

Obsidian

Volcanic Glass (SiO2)

Obsidian (Volcanic Glass (Amorphous Silicon Dioxide)) — igneous

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

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

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Obsidian (Volcanic Glass (SiO2)) — igneous

Obsidian

Volcanic Glass (SiO2)

Obsidian (Volcanic Glass (Amorphous Silica)) — igneous

Obsidian

Volcanic Glass (Amorphous Silica)

Jet (Lignite (Anthracite-grade compact coal)) — sedimentary

Jet

Lignite (Anthracite-grade compact coal)

Obsidian (Volcanic glass) — igneous

Obsidian

Volcanic glass

Obsidian (Volcanic Glass (felsic composition)) — igneous

Obsidian

Volcanic Glass (felsic composition)

Probable amber fragment (Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)) — gemstone

Probable amber fragment

Amber (fossilized plant resin; chiefly amorphous organic resin, commonly dominated by succinite)

Limonite (Ironstone) (Limonite (mixture of hydrated iron(III) oxide-hydroxides)) — mineral

Limonite (Ironstone)

Limonite (mixture of hydrated iron(III) oxide-hydroxides)

Obsidian (Volcanic Glass (comprised primarily of SiO2)) — Igneous

Obsidian

Volcanic Glass (comprised primarily of SiO2)

Obsidian (Volcanic Glass (Silicon Dioxide with impurities)) — igneous

Obsidian

Volcanic Glass (Silicon Dioxide with impurities)

Obsidian (Obsidian (Amorphous volcanic glass, SiO2 with impurities)) — igneous

Obsidian

Obsidian (Amorphous volcanic glass, SiO2 with impurities)

Opal (Hydrated Amorphous Silica (SiO2·nH2O)) — Mineral

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Obsidian (Obsidian (Volcanic Glass, SiO2 + impurities)) — igneous

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Mahogany Obsidian (Volcanic Glass with Hematite (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic Glass with Hematite (SiO2 + Fe2O3)

Common Opal with Host Rock (Opal (Hydrated silica, SiO2·nH2O)) — mineral

Common Opal with Host Rock

Opal (Hydrated silica, SiO2·nH2O)

Green Opal (Prase Opal) (SiO2 · nH2O (Hydrated Silicon Dioxide)) — mineral

Green Opal (Prase Opal)

SiO2 · nH2O (Hydrated Silicon Dioxide)