Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
igneous
Category
Organic Mineraloid And Mineral
Browse organic mineraloid and mineral specimens identified by the Rock Identifier community.
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Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
sedimentary
Cullet Glass (Slag)
Amorphous Silicon Dioxide (Man-made)
Mineraloid
Obsidian
Volcanic glass (Amorphous silicon dioxide)
igneous
Obsidian
Volcanic glass
igneous
Mahogany Obsidian
Volcanic Glass (SiO2 with Fe/Mg oxides)
igneous
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Black Obsidian
Volcanic glass (Amorphous silicates)
igneous
Green Opal
Hydrated amorphous silica (SiO2·nH2O) with inclusions
mineraloid
Sea Glass (Frosted Quartz/Glass)
Amorphous Silicon Dioxide (SiO2)
Mineraloid
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
igneous
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial byproduct)
mineraloid
Obsidian
Obsidian (principally SiO2 with MgO and Fe3O4)
igneous
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
mineral
Mahogany Obsidian
Volcanic glass (SiO2 + Fe2O3)
igneous
Opalite
Synthetic glass (SiO2 + metal additions)
mineraloid
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
igneous
Snowflake Obsidian
Obsidian with Spherulitic Cristobalite (SiO2)
igneous
Green Opal (Prase Opal)
SiO2 · nH2O (Hydrated Silicon Dioxide)
mineral
Snowflake Obsidian
Volcanic glass containing Spherulites (SiO2)
igneous
Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Amber and Citrine Quartz
Succinite (Amber) and Silicon Dioxide (SiO2 / Citrine)
mineral
Amber
Succinite (fossilized resin, C10H16O)
mineral
Amber
Succinicum (C10H16O)
mineral
Opalite
Synthetic Glass (Hydrated Crystalline Silicon Dioxide simulation)
mineral
Petrified Wood
Silicified wood (Quartz replacement, SiO2)
fossil
Amber
Resinite / Fossilized Tree Resin
mineral
Precious Coral
Corallium rubrum (Calcium carbonate with trace carotene)
Organic gemstone / Sedimentary mineraloid
Kidney Stone
Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)
mineral
Soil with Mineral Detritus and Quartz Fragments
Regolith / Silicate Mineral Aggregate
sedimentary
Fossilized Bone
Permineralized Vertebrate Bone
fossil
Orange cabochon gemstone, likely amber or amber-like resin
Natural amber: fossilized plant resin (organic mineraloid), commonly succinite; exact identification requires testing
gemstone
Fossilized Bone
Petrified Bone / Biogenic Sedimentary
fossil
Fossilized Bone
Vertebrate fossil (mineralized bone)
fossil
Jade (likely Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral/Mineraloid
Natural Pearl
Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3
mineral
Limestone or Sandstone Cobble
Sedimentary rock (Calcium carbonate or Quartz based)
sedimentary
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)
Baltic Amber (Butterscotch variety)
Succinite
Organic Gemstone/Mineraloid
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (C10H16O)
Organic Gemstone (Mineraloid)
Amber
Succinite (C10H16O)
mineral
Amber
Fossilized Tree Resin
gemstone