Black Obsidian
Obsidian (Volcanic Glass, SiO2+)
Category
Browse organic mineraloid and mineral specimens identified by the Rock Identifier community.
Black Obsidian
Obsidian (Volcanic Glass, SiO2+)
Black Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Obsidian
Obsidian (Volcanic Glass)
Amber
Succinite (fossilized tree resin)
Amber
Succinates
Obsidian
Volcanic Glass (SiO2)
Limonite (Iron Ore)
Limonite (Hydrous ferric oxides), generic formula FeO(OH)·nH2O
Amber (likely a small polished amber piece)
Natural fossil resin; amber is an organic mineraloid, not a crystalline mineral. The image alone cannot confirm authenticity.
Opal
Hydrated Silica (SiO2·nH2O)
Polished mahogany obsidian
Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)
Polished mahogany obsidian
Volcanic glass; predominantly silica-rich rhyolitic composition (SiO₂)
Polished black obsidian
Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)
Black Obsidian
Volcanic Glass (SiO2)
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Obsidian
Volcanic Glass (70-75% SiO2)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Obsidian
Volcanic Glass (SiO2)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Glass
Amorphous Silicon Dioxide (SiO2)
Common Opal (Green Opal / Pistachio Opal)
Hydrated silica (SiO2·nH2O)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Opal ring
Common opal, likely synthetic or assembled blue-green opal (hydrated amorphous silica, SiO₂·nH₂O)
Obsidian (likely black obsidian)
Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)
Obsidian (likely black obsidian)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
Obsidian
Amorphous volcanic glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Limonite (Iron Stone/Goethite)
Limonite (mixture of hydrated iron oxides, primarily Goethite: α-FeO(OH))
Limonite (Iron Ore Congcretion)
Limonite (a mixture of hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)
Green Opal or Yellow Opal
Hydrated Silica (SiO2·nH2O)
Mahogany Obsidian
Volcanic Glass with Hematite (SiO2 + Fe2O3)
Obsidian
Volcanic glass
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)
Obsidian (black volcanic glass)
Obsidian; predominantly silica-rich volcanic glass, commonly rhyolitic (approximately 70–75% SiO₂)
Tumbled black obsidian (likely)
Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, amorphous)
Obsidian (likely black volcanic glass)
Obsidian; silica-rich, noncrystalline volcanic glass, typically rhyolitic (approximately 70–75% SiO₂)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions
Black Obsidian
Volcanic Glass (SiO2 + MgO / Fe3O4)
Black Obsidian
Volcanic Glass (SiO2)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
Obsidian
Obsidian (volcanic glass; primarily SiO2)