Obsidian
Volcanic glass
igneous
Category
Mineraloid (Anthropogenic)
Browse mineraloid (anthropogenic) specimens identified by the Rock Identifier community.
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Mahogany Obsidian
Volcanic Glass (SiO2 with Fe/Mg oxides)
igneous
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Asphalt (Bituminous pavement)
Bituminous concrete / Asphalt
Sedimentary (Anthropogenic)
Concrete Fragment
Hardened Portland cement and mineral aggregate
sedimentary (anthropogenic)
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various additives
Man-made material (Anthropogenic 'mineraloid')
Common Opal (Potch)
Hydrated Silica (SiO2·nH2O)
mineral
Black Obsidian
Volcanic glass (Amorphous silicates)
igneous
Limonite with Quartz (Gossan)
Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)
Mineral
White Opal (Common)
Hydrated Silica (SiO2·nH2O)
mineral
Cantera Opal (Mexican Fire Opal in Rhyolite Matrix)
Hydrated amorphous silica in rhyolite (SiO2·nH2O in volcanic matrix)
gemstone
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Obsidian
Obsidian (principally SiO2 with MgO and Fe3O4)
igneous
Asphalt fragment
Bituminous concrete
anthropogenic material
Paper (Cellulose)
Cellulose (C6H10O5)n
Organic (Anthropogenic)
Green Slag Glass
Amorphous Silicon Dioxide (with metallic impurities)
Igneous (Anthropogenic)
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
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)
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
igneous
Red Sandstone
Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)
sedimentary
Amber-set ring
Amber (fossilized plant resin; organic mineraloid), set in a metal ring
gemstone
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Metal Chain (Likely Steel or a Steel Alloy)
Steel (primarily iron and carbon); specific alloy unknown
Man-made Object (Metal/Alloy)
Ferrochrome Slag
Anthropogenic silicate/oxide glass (Complex silicate matrix with Cr-Fe-Si inclusions)
Industrial byproduct (often confused with igneous rocks or meteorites)
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
mineral
Amber (likely raw amber)
Fossilized tree resin; organic mineraloid, commonly containing succinite (not a true mineral)
gemstone
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
igneous
Amber
Succinite (fossilized tree resin)
Organic Mineraloid
Amber
Succinate (Succinite for Baltic varieties)
Organic Mineraloid
Man-made Glass (Tumbled/Shaped)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Mineraloid (synthetic)
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
mineraloid (synthetic)
Synthetic Convention Badge (Plastic/PVC)
Polyvinyl Chloride (PVC) / Polycarbonate
mineraloid (synthetic)
Amber
Succinite (C10H16O)
Mineraloid (Organic)
Jade (likely Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral/Mineraloid
Jade
Jadeite or Nephrite
Mineral/Mineraloid
Amber
Succinite
Organic Mineraloid
Amber
Succinite (with formula approximately C10H16O)
Organic mineraloid
Pearl (Cultured or Natural)
Aragonite (CaCO3) with Conchiolin
Organic Mineraloid
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary (or mineraloid)
Amber
Succinite (Fossilized Tree Resin)
Organic Mineraloid
Opalite (Synthetic Moonstone/Opal)
Synthetic Silica Glass
mineraloid (synthetic)
Amber
Succinite (Fossilized Tree Resin), C10H16O
Organic Mineraloid