Rock Identifier

Category

Organic (Mineraloid)

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

Learn about Organic (Mineraloid) in the encyclopedia

Shungite

Sapropel

Bituminous Shale

Bituminous Shale

Black Shale

Petrified Wood

Amber

Jet

Oil Shale

Peat

Pearl

Lizard Skin Jasper

Opalized Wood

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

Limonite (Ironstone)

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

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Opal (in Jewelry Setting) (Hydrated Silicon Dioxide (SiO2·nH2O)) — gemstone

Opal (in Jewelry Setting)

Hydrated Silicon Dioxide (SiO2·nH2O)

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

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Obsidian arrowhead (Volcanic glass; predominantly SiO₂, with minor feldspar, pyroxene, and iron oxides) — igneous

Obsidian arrowhead

Volcanic glass; predominantly SiO₂, with minor feldspar, pyroxene, and iron oxides

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

Mahogany Obsidian

Volcanic Glass with Hematite (SiO2 + Fe2O3)

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

Black Obsidian

Volcanic Glass (SiO2 + impurities like Fe3O4)

Opal (Hydrated silica (SiO2 "NH2O)) — mineraloid

Opal

Hydrated silica (SiO2 "NH2O)

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

Snowflake Obsidian

Spherulitic Obsidian (Volcanic Glass with Cristobalite inclusions)

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

Precious Opal

SiO2·nH2O (Hydrated Silicon Dioxide)

Black obsidian (likely) (Volcanic glass; primarily silica-rich, noncrystalline SiO₂ composition) — igneous

Black obsidian (likely)

Volcanic glass; primarily silica-rich, noncrystalline SiO₂ composition

Polished black stone, likely black obsidian (Obsidian (volcanic glass), primarily rhyolitic silica glass) — igneous

Polished black stone, likely black obsidian

Obsidian (volcanic glass), primarily rhyolitic silica glass

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

Obsidian

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

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

Obsidian

Volcanic glass (mainly SiO2 with inclusions)

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

Mahogany Obsidian

Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)

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)

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

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)

Black Obsidian (Obsidian (Amorphous Silicon Dioxide)) — igneous

Black Obsidian

Obsidian (Amorphous Silicon Dioxide)

Snowflake Obsidian (Volcanic Glass with Cristobalite Inclusions) — igneous

Snowflake Obsidian

Volcanic Glass with Cristobalite Inclusions

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

Amber

Succinite (fossilized tree resin)

mineraloid / sedimentary organic material

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)

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

Green Opal or Yellow Opal

Hydrated Silica (SiO2·nH2O)

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

Green Opal

Hydrated amorphous silica (SiO2·nH2O) with inclusions

Cobalt Glass Slug (Man-made Glass) (Amorphous Silica with Cobalt Oxide (SiO2 + CoO)) — mineraloid

Cobalt Glass Slug (Man-made Glass)

Amorphous Silica with Cobalt Oxide (SiO2 + CoO)

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

Opalite

Synthetic Glass (Amorphized Silicon Dioxide)

Common Opal (Green Opal / Pistachio Opal) (Hydrated silica (SiO2·nH2O)) — mineraloid

Common Opal (Green Opal / Pistachio Opal)

Hydrated silica (SiO2·nH2O)

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

Cullet Glass (Slag)

Amorphous Silicon Dioxide (Man-made)

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

Tektite (Indochinite)

Impact Glass (SiO2 + Al2O3)

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

Slag (Industrial Glass)

Anthropogenic Amorphous Vitreous Silicate

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

Common Opal

SiO2·nH2O (Hydrated Silicon Dioxide)

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

Green Opal

Hydrated amorphous silica (SiO2·nH2O)

Pearl (Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin) — mineraloid

Pearl

Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin

Conch Pearl (Calcareous concretion (CaCO3)) — mineraloid

Conch Pearl

Calcareous concretion (CaCO3)