Mahogany Obsidian
Volcanic Glass (Silicate: SiO2 + Fe2O3)
Category
Browse mineralogical specimens identified by the Rock Identifier community.
Mahogany Obsidian
Volcanic Glass (Silicate: SiO2 + Fe2O3)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Obsidian
Volcanic Glass (SiO2 rich)
Limonite (with Pyrite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Limonite (Ironstone Concretion)
Limonite (Hydrated iron(III) oxide-hydroxide, mixtures of FeO(OH)·nH2O)
Bumblebee Jasper
Calcite with Arsenic and Sulfur inclusions
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)
Snowflake Obsidian
Volcanic Glass (SiO2) with Cristobalite inclusions
Obsidian
Volcanic Glass (Silica / SiO2)
Mahogany Obsidian
Volcanic glass (Silicon Dioxide with Hematite/Magnetite inclusions)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Spherulitic Volcanic Glass (SiO2 + impurities)
Limonite Concretion
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
Obsidian
Volcanic Glass (predominantly SiO2)
Tumbled black stone, likely black obsidian
Obsidian — natural volcanic glass, primarily SiO₂
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Mahogany Obsidian
Volcanic glass containing Magnetite/Hematite
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Obsidian
Volcanic Glass (SiO2)
Snowflake Obsidian
Obsidian with Spherulitic Cristobalite (SiO2)
Limonite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Mahogany Obsidian
Obsidian (SiO2 + Fe2O3)
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
Yellow Ocher (Limonite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Precious Coral (Red Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
Black Opal (Triplet)
Hydrated Silica (SiO2·nH2O)
Obsidian
Volcanic Glass (Amorphous Silica)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Obsidian
Volcanic glass
Obsidian
Volcanic Glass (felsic composition)
Obsidian
Volcanic Glass (Silicon Dioxide with impurities)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 with impurities)
Snowflake Obsidian
Volcanic glass containing Spherulites (SiO2)
Amber
Succinite (with a generalized formula of C10H16O)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (Amorphous SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)