Common Opal with Host Rock
Opal (Hydrated silica, SiO2·nH2O)
Category
Browse mineralogical specimens identified by the Rock Identifier community.
Common Opal with Host Rock
Opal (Hydrated silica, SiO2·nH2O)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Mahogany Obsidian
Obsidian (volcanic glass with hematite/magnetite inclusions)
Limonite (Ironstone) Concretion
FeO(OH)·nH2O (Hydrous ferric oxide)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Volcanic Glass with Spherulite inclusions (Chemical composition: 70–75% SiO2 + MgO, Fe3O4)
Obsidian (Black Obsidian)
Obsidian (Volcanic Glass)
Limonite (Yellow Ochre)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
Snowflake Obsidian
Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)
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)
Polished amber
Amber (fossilized plant resin), commonly succinite; organic mineraloid rather than a true mineral
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)
Black Obsidian
Volcanic glass (Amorphous silicates)
Common Opal (Potch)
Hydrated Silica (SiO2·nH2O)
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)
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
Orange cabochon gemstone, likely amber or amber-like resin
Natural amber: fossilized plant resin (organic mineraloid), commonly succinite; exact identification requires testing
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
Amber
Amber (Fossilized Tree Resin)
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
Amber
Succinite (fossilized tree resin)
Amber
Succinate (Succinite for Baltic varieties)
Man-made Glass (Tumbled/Shaped)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
Synthetic Convention Badge (Plastic/PVC)
Polyvinyl Chloride (PVC) / Polycarbonate
Amber
Succinite (C10H16O)
Jade (likely Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Amber
Succinite
Amber
Succinite (with formula approximately C10H16O)