Rock Identifier

Category

Mineraloid (Organic)

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

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

Limonite (Iron Ore)

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

Anthracite Coal (Anthracite (Carbon-rich mineraloid)) — metamorphic

Anthracite Coal

Anthracite (Carbon-rich mineraloid)

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

Green Opal

Hydrated Silica (SiO2·nH2O)

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

Opal

Hydrated Silica (SiO2·nH2O)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

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

Amber

Succinite (fossilized tree resin)

mineraloid / sedimentary organic material

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

Limonite (Iron Ore)

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

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

Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

Obsidian (Volcanic Glass (SiO2)) — igneous

Obsidian

Volcanic Glass (SiO2)

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

Jet

Lignite (Anthracite-grade compact coal)

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

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

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

Obsidian

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

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)

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

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

Limonite (Iron Stone/Ocher)

Limonite (FeO(OH)·nH2O)

Snowflake Obsidian (Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)) — igneous

Snowflake Obsidian

Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)

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

Snowflake Obsidian

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

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

Obsidian

Amorphous volcanic glass (primarily SiO2)

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

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

Black Obsidian

Volcanic Glass (SiO2 + impurities like Fe3O4)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Snowflake Obsidian (Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions) — igneous

Snowflake Obsidian

Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions

Obsidian (Volcanic Glass (SiO2)) — igneous

Obsidian

Volcanic Glass (SiO2)

Opal (Hydrated amorphous silica (SiO2·nH2O)) — mineral

Opal

Hydrated amorphous silica (SiO2·nH2O)

Precious Coral (Corallium rubrum (Calcium carbonate with trace carotene)) — Organic gemstone / Sedimentary mineraloid

Precious Coral

Corallium rubrum (Calcium carbonate with trace carotene)

Organic gemstone / Sedimentary mineraloid

Snowflake Obsidian (Volcanic glass containing Spherulitic Cristobalite (SiO2)) — igneous

Snowflake Obsidian

Volcanic glass containing Spherulitic Cristobalite (SiO2)

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

Obsidian

Volcanic Glass (70-75% SiO2)

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

Mahogany Obsidian

Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)

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

Opal

Hydrated Silica (SiO2·nH2O)

Gold Sheen Obsidian (Obsidian (volcanic glass with SiO2 + gas inclusions)) — igneous

Gold Sheen Obsidian

Obsidian (volcanic glass with SiO2 + gas inclusions)

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)

Obsidian (Volcanic Glass (SiO2)) — igneous

Obsidian

Volcanic Glass (SiO2)

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

White Precious Opal

Hydrated Silica (SiO2·nH2O)

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

Limonite (Yellow Ochre)

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

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

Black Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

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)

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

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

Common Opal in Host Rock

Hydrated Silica (SiO2·nH2O)

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

Common Opal

Hydrated Amorphous Silica (SiO2·nH2O)

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

Limonite (Ironstone)

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