Obsidian
Volcanic Glass (Amorphous SiO2)
Category
Browse organic mineraloid specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (Amorphous SiO2)
Obsidian
Volcanic Glass (SiO2 rich)
Fulgurite
Fulgurite (Lechatelierite-rich fused silica)
Limonite (Iron Ore)
Limonite (Hydrated Iron Oxide, FeO(OH)·nH2O)
Amber
Succinite (Resinite)
Obsidian
Volcanic Glass (70% or more SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Obsidian
Obsidian (Amorphous volcanic glass, predominantly SiO2)
Obsidian
Volcanic glass
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Likely obsidian (possibly tektite or slag glass)
Volcanic glass; primarily SiO₂, noncrystalline
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Limonite (Iron Ore)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Jet
Lignite (Anthracite-grade compact coal)
Obsidian
Volcanic Glass (SiO2)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Limonite/Ironstone
Limonite (FeO(OH)·nH2O)
Amber
Succinite (specifically for Baltic amber); Approximate formula: C10H16O
Green Opal
Hydrated Silica (SiO2·nH2O)
Opal (in Jewelry Setting)
Hydrated Silicon Dioxide (SiO2·nH2O)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Precious Opal
SiO2·nH2O (Hydrated Silicon Dioxide)
Opal
Hydrated Silica (SiO2·nH2O)
Limonite (Ironstone)
Limonite (mixture of hydrated iron(III) oxide-hydroxides)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
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)
Opal
Hydrated amorphous silica (SiO2·nH2O)
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)
Limonite (Iron Stone/Ocher)
Limonite (FeO(OH)·nH2O)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Obsidian
Amorphous volcanic glass (primarily SiO2)