Limonite/Ironstone
Limonite (FeO(OH)·nH2O)
Category
Browse mineral (or mineraloid if microcrystalline) specimens identified by the Rock Identifier community.
Limonite/Ironstone
Limonite (FeO(OH)·nH2O)
Common Opal
SiO2·nH2O (Hydrated Silicon Dioxide)
Gold Sheen Obsidian
Volcanic Glass (SiO2 + impurities)
Polished mahogany obsidian
Volcanic glass; primarily silica-rich rhyolitic composition (approximately 70–75% SiO₂)
Obsidian
Obsidian (Volcanic Glass)
Obsidian (Gold Sheen)
Obsidian (SiO2 + impurities)
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Obsidian
Volcanic Glass (SiO2 + impurities)
Bumblebee Jasper
Calcite with Arsenic and Sulfur inclusions
Mahogany Obsidian
Volcanic glass containing Magnetite/Hematite
Limonite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
Obsidian (likely black volcanic glass)
Obsidian; primarily amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (Silica / SiO2)
Obsidian
Volcanic Glass (predominantly SiO2)
Opal
Hydrated silica (SiO2 "NH2O)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Opal
Hydrated silica (SiO2·nH2O)
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Yellow Ocher (Limonite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Precious Coral (Red Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
Amber (Copal)
Fossilized Tree Resin
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Amber
Succinates
Shungite
Carbon-rich mineraloid (Amorphous carbon)
Shungite
Shungite (carbon-rich Precambrian mineraloid)
Obsidian (volcanic glass), likely black obsidian
Rhyolitic volcanic glass; predominantly amorphous SiO₂
Obsidian (likely black obsidian)
Volcanic glass, predominantly rhyolitic to dacitic silica-rich melt; approximate composition ~70–75% SiO₂
Black obsidian
Volcanic glass, primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)
Tumbled black stone, likely obsidian
Obsidian — volcanic glass, chiefly silica-rich rhyolitic composition
Tumbled black obsidian (likely)
Volcanic glass; chiefly silica-rich rhyolitic glass (SiO₂)
Tumbled black stone, likely black obsidian
Obsidian — natural volcanic glass, primarily SiO₂
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Amber
Succinite (with a generalized formula of C10H16O)
Amber
Succinite (Fossilized Tree Resin)
Amber (Raw)
Succinite (Fossilized Resin)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Amber
Succinates (Fossilized Tree Resin)