Limonite (Ironstone)
Limonite (mixture of hydrated iron(III) oxide-hydroxides)
Category
Browse mineraloid (synthetic) specimens identified by the Rock Identifier community.
Limonite (Ironstone)
Limonite (mixture of hydrated iron(III) oxide-hydroxides)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Ruby / Red Corundum
Al2O3 (Aluminum Oxide with Chromium trace)
Clear Quartz crystals on a Matrix base (Geode fragment)
Silicon Dioxide (SiO2)
Green gemstone ring, likely emerald simulant or jade
Uncertain; possible beryl (emerald, Be₃Al₂Si₆O₁₈) or jadeite (NaAlSi₂O₆), but the blurred image may show synthetic glass or another treated stone
Amber (Simulated/Faturan Style)
Resin mix (Likely Phenolic/Celluloid if synthetic, Succinite if natural)
Red gemstone ring, likely garnet or synthetic ruby
Possibly almandine garnet (Fe₃Al₂(SiO₄)₃) or corundum/ruby (Al₂O₃); image alone cannot distinguish
Synthetic Costume Glove (Paws)
Polyethylene terephthalate (Polyester) & Polyurethane blend
Red gemstone ring, possibly synthetic ruby or red glass
Unidentified red stone; ruby is corundum (Al₂O₃), but the image cannot confirm its identity
Obsidian arrowhead
Volcanic glass; predominantly SiO₂, with minor feldspar, pyroxene, and iron oxides
Mahogany Obsidian
Volcanic Glass with Hematite (SiO2 + Fe2O3)
Black Obsidian
Volcanic Glass (SiO2 + impurities like Fe3O4)
Opal
Hydrated silica (SiO2 "NH2O)
Snowflake Obsidian
Spherulitic Obsidian (Volcanic Glass with Cristobalite inclusions)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
Obsidian
Volcanic Glass (SiO2)
Amber
Amber (C10H16O)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Amber with Inclusion
Succiniferous fossil resin (C10H16O)
Black Pearl (Tahitian Pearl)
Aragonite / Calcite (CaCO3) with Conchiolin
Small clear crystal, possibly quartz or glass-like gemstone
Uncertain; likely quartz (SiO₂), but the image is insufficient to exclude man-made glass or cubic zirconia
Plastic Building Toy (Lego-style piece)
Acrylonitrile Butadiene Styrene (ABS)
Synthetic Costume Accessory (Non-Geological)
Polyester and Acrylic Fiber (Anthropogenic polymer)
Lapis Lazuli
Lazurite-dominant metamorphic rock, Na8[Al6Si6O24]n(S,Cl,SO4,OH)2
Synthetic Faux Fur Fursuit
Polyacrylonitrile / Polyester (Synthetic Textile)
Opalite
Synthetic Glass (Simulated Opal)
Cubic Zirconia
Cubic Zirconium Dioxide (ZrO2)
Cubic Zirconia
Zirconium dioxide (ZrO2)
Black obsidian (likely)
Volcanic glass; primarily silica-rich, noncrystalline SiO₂ composition
Polished black stone, likely black obsidian
Obsidian (volcanic glass), primarily rhyolitic silica glass
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Obsidian
Obsidian (Volcanic Glass)
Limonite (Iron Stone/Ocher)
Limonite (FeO(OH)·nH2O)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Limonite/Goethite on Shale
Hydrous ferric oxides (FeO(OH)·nH2O) often associated with argillaceous rock
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Snowflake Obsidian
Volcanic Glass with Cristobalite inclusions (70–75% SiO2)
Black Obsidian
Obsidian (Amorphous Silicon Dioxide)
Snowflake Obsidian
Volcanic Glass with Cristobalite Inclusions