Rock Identifier

Category

Organic Crystal (Mineraloid)

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

Limonite Concretion (Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)) — sedimentary

Limonite Concretion

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

Opalite (Man-made opalescent glass) — gemstone

Opalite

Man-made opalescent glass

Snowflake Obsidian (Spherulitic Volcanic Glass (SiO2 + impurities)) — igneous

Snowflake Obsidian

Spherulitic Volcanic Glass (SiO2 + impurities)

Obsidian (Volcanic Glass (Silica / SiO2)) — igneous

Obsidian

Volcanic Glass (Silica / SiO2)

Tektite (likely Australite) (Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)) — Mineral (specifically a mineraloid)

Tektite (likely Australite)

Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)

Mineral (specifically a mineraloid)

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

Limonite (Iron Ore)

Hydrous ferric oxides (FeO(OH)·nH2O)

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

Mahogany Obsidian

Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)

Limonite (Iron Ore/Sandstone mixture) (Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix) — mineral

Limonite (Iron Ore/Sandstone mixture)

Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix

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

Obsidian

Volcanic Glass (predominantly SiO2, approximately 70% or more)

Yellow Ocher (Limonite) (Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O) — mineral

Yellow Ocher (Limonite)

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

Amber (and Citrine Quartz) (Succinite (Amber) and Silicon Dioxide (SiO2)) — Organic Mineraloid and Mineral

Amber (and Citrine Quartz)

Succinite (Amber) and Silicon Dioxide (SiO2)

Organic Mineraloid and Mineral

Baltic Amber (Butterscotch variety) (Succinite) — Organic Gemstone/Mineraloid

Baltic Amber (Butterscotch variety)

Succinite

Organic Gemstone/Mineraloid

Limonite (Iron Ore) (Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)) — Mineral

Limonite (Iron Ore)

Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)

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

Obsidian

Obsidian (volcanic glass; primarily SiO2)

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

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

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

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)

Snowflake Obsidian (Volcanic glass containing Spherulites (SiO2)) — igneous

Snowflake Obsidian

Volcanic glass containing Spherulites (SiO2)

Pearl (Biogenic Mineraloid) (Calcium carbonate (CaCO3) primarily as Aragonite) — mineral

Pearl (Biogenic Mineraloid)

Calcium carbonate (CaCO3) primarily as Aragonite

Obsidian (Obsidian (Volcanic Glass)) — igneous

Obsidian

Obsidian (Volcanic Glass)

Obsidian (Black Obsidian) (Obsidian (Volcanic Glass)) — igneous

Obsidian (Black Obsidian)

Obsidian (Volcanic Glass)

Limonite (Ironstone) Concretion (FeO(OH)·nH2O (Hydrous ferric oxide)) — sedimentary

Limonite (Ironstone) Concretion

FeO(OH)·nH2O (Hydrous ferric oxide)

Snowflake Obsidian (Volcanic Glass with Spherulite inclusions (Chemical composition: 70–75% SiO2 + MgO, Fe3O4)) — igneous

Snowflake Obsidian

Volcanic Glass with Spherulite inclusions (Chemical composition: 70–75% SiO2 + MgO, Fe3O4)

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

Obsidian

Volcanic Glass (SiO2 + impurities)

Obsidian (Volcanic glass (Amorphous silicon dioxide)) — igneous

Obsidian

Volcanic glass (Amorphous silicon dioxide)

Amber (Resinite / Fossilized Tree Resin) — mineral

Amber

Resinite / Fossilized Tree Resin

Opalite (Synthetic Glass (Hydrated Crystalline Silicon Dioxide simulation)) — mineral

Opalite

Synthetic Glass (Hydrated Crystalline Silicon Dioxide simulation)

Mahogany Obsidian (Volcanic glass containing Magnetite/Hematite) — igneous

Mahogany Obsidian

Volcanic glass containing Magnetite/Hematite

Obsidian (Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)) — igneous

Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Mahogany Obsidian Arrowhead (Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)) — igneous

Mahogany Obsidian Arrowhead

Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)

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

Black Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)

Mahogany Obsidian (Volcanic Glass (SiO2 with Fe/Mg oxides)) — igneous

Mahogany Obsidian

Volcanic Glass (SiO2 with Fe/Mg oxides)

Limonite with Quartz (Gossan) (Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)) — Mineral

Limonite with Quartz (Gossan)

Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)

Opalite (Man-made Glass (Synthetic Opalized Glass)) — gemstone

Opalite

Man-made Glass (Synthetic Opalized Glass)

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

Common Opal (Potch)

Hydrated Silica (SiO2·nH2O)

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

Obsidian

Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)

Limonite and Goethite (Ironstone) (Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)) — sedimentary

Limonite and Goethite (Ironstone)

Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)

Naga Silver-Inlaid Ebony and Bone/Horn Beads (Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay) — Organic (Anthropological Artifact)

Naga Silver-Inlaid Ebony and Bone/Horn Beads

Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay

Organic (Anthropological Artifact)

Polished black stone egg, probably black obsidian (Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements) — gemstone

Polished black stone egg, probably black obsidian

Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements

Ambergris (Ambrein (C30H52O)) — mineraloid / organic geological substance

Ambergris

Ambrein (C30H52O)

mineraloid / organic geological substance

Manganese Dendrite on Siltstone (Manganese Oxide (pyrolusite or psilomelane) Dendrites) — mineral/sedimentary

Manganese Dendrite on Siltstone

Manganese Oxide (pyrolusite or psilomelane) Dendrites

mineral/sedimentary

Ambergris (Physeter macrocephalus excreta (Ambergris)) — mineraloid / organic geological find

Ambergris

Physeter macrocephalus excreta (Ambergris)

mineraloid / organic geological find

Black Limestone with Calcite Veining (Bituminous Limestone (CaCO3 with Organic Carbon inclusions)) — sedimentary

Black Limestone with Calcite Veining

Bituminous Limestone (CaCO3 with Organic Carbon inclusions)