Snowflake Obsidian
Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)
Category
Browse organic mineraloid specimens identified by the Rock Identifier community.
Snowflake Obsidian
Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)
Black Opal (Triplet)
Hydrated Silica (SiO2·nH2O)
Obsidian
Volcanic glass (silica-rich rhyolitic melt; primarily SiO₂)
Obsidian
Obsidian (Extrusive Volcanic Glass)
Obsidian
Volcanic Glass (comprised primarily of SiO2)
Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
Mahogany Obsidian
Volcanic glass (SiO2 + Fe2O3)
Opalite
Synthetic Glass (Hydrated Crystalline Silicon Dioxide simulation)
Obsidian
Volcanic glass (Amorphous silicon dioxide)
Obsidian
Volcanic glass
Mahogany Obsidian
Volcanic Glass (SiO2 with Fe/Mg oxides)
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Common Opal (Potch)
Hydrated Silica (SiO2·nH2O)
Black Obsidian
Volcanic glass (Amorphous silicates)
Limonite with Quartz (Gossan)
Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)
White Opal (Common)
Hydrated Silica (SiO2·nH2O)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Obsidian
Obsidian (principally SiO2 with MgO and Fe3O4)
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
Raw Amber / Resin Mineral
Succinite (Fossilized Tree Resin)
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
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)
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Red Sandstone
Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)
Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
Amber and Citrine Quartz
Succinite (Amber) and Silicon Dioxide (SiO2 / Citrine)
Amber
Succinite (fossilized resin, C10H16O)
Amber
Succinicum (C10H16O)
Naga Silver-Inlaid Ebony and Bone/Horn Beads
Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
Amber
Resinite / Fossilized Tree Resin
Limestone (specifically Bituminous or Carbonaceous Limestone)
Calcium Carbonate (CaCO3) with Organic Impurities
Petrified Wood
Silicified wood (Quartz replacement, SiO2)
Chert (Agatized/Chalcedony variety)
Microcrystalline Quartz (SiO2)
Pyritic Shale
Carbonaceous Shale with Iron Pyrite (FeS2)
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
Fossiliferous Shale
Carbonaceous Shale (with potential plant/aquatic fossils)
Fossilized Bone
Vertebrate fossil (mineralized bone)
Mother of Pearl (Nacre)
Aragonite (CaCO3) with Organic Matrix
Fossilized Wood / Petrified Wood
Petrified Wood (Silicified Flora)
Black Limestone
Bituminous Limestone (Calcium Carbonate - CaCO3)
Chert (Green Fossilized Algae or Jasper)
Silicon Dioxide (SiO2)