Obsidian
Volcanic Glass (comprised primarily of SiO2)
Igneous
Category
Organic Mineraloid
Browse organic mineraloid specimens identified by the Rock Identifier community.
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Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
igneous
Mahogany Obsidian
Volcanic glass (SiO2 + Fe2O3)
igneous
Opalite
Synthetic Glass (Hydrated Crystalline Silicon Dioxide simulation)
mineral
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
Common Opal (Potch)
Hydrated Silica (SiO2·nH2O)
mineral
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
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
sedimentary
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Obsidian
Obsidian (principally SiO2 with MgO and Fe3O4)
igneous
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
igneous
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)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Raw Amber / Resin Mineral
Succinite (Fossilized Tree Resin)
gemstone
Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
gemstone
Amber and Citrine Quartz
Succinite (Amber) and Silicon Dioxide (SiO2 / Citrine)
mineral
Amber
Succinite (fossilized resin, C10H16O)
mineral
Amber
Succinicum (C10H16O)
mineral
Naga Silver-Inlaid Ebony and Bone/Horn Beads
Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay
Organic (Anthropological Artifact)
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
igneous
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
sedimentary
Amber
Resinite / Fossilized Tree Resin
mineral
Limestone (specifically Bituminous or Carbonaceous Limestone)
Calcium Carbonate (CaCO3) with Organic Impurities
sedimentary
Red Sandstone
Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)
sedimentary
Petrified Wood
Silicified wood (Quartz replacement, SiO2)
fossil
Ambergris
Physeter macrocephalus excreta (Ambergris)
mineraloid / organic geological find
Fossiliferous Shale
Carbonaceous Shale (with potential plant/aquatic fossils)
sedimentary
Chert (Agatized/Chalcedony variety)
Microcrystalline Quartz (SiO2)
sedimentary
Ambergris
Ambrein (C30H52O)
mineraloid / organic geological substance
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)
Jade (likely Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral/Mineraloid
Jade
Jadeite or Nephrite
Mineral/Mineraloid
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary (or mineraloid)
Opalite (Synthetic Moonstone/Opal)
Synthetic Silica Glass
mineraloid (synthetic)
Opalite
Synthetic Opalised Glass
mineraloid (synthetic)