Obsidian
Volcanic glass (high silica volcanic rock)
Category
Browse mineraloid (impact glass) specimens identified by the Rock Identifier community.
Obsidian
Volcanic glass (high silica volcanic rock)
Obsidian
Volcanic Glass (SiO2 + impurities)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite inclusions)
Polished black obsidian
Volcanic glass; primarily silica-rich rhyolitic glass (approximately 70–80% SiO₂)
Black obsidian
Volcanic glass, primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)
Obsidian (likely black obsidian)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
Obsidian (black volcanic glass)
Obsidian; predominantly silica-rich volcanic glass, commonly rhyolitic (approximately 70–75% SiO₂)
Obsidian (likely black volcanic glass)
Obsidian; predominantly silica-rich rhyolitic volcanic glass (approximately 70– on 80% SiO₂)
Obsidian
Volcanic Glass (Silica / SiO2)
Obsidian
Obsidian (Volcanic Glass; SiO2 content > 70%)
Moldavite
SiO2 (+ Al2O3, FeO, K2O) - Natural Tektite Glass
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions
Black Obsidian
Obsidian (Volcanic Glass, ~70% SiO2)
Quartz (Sea Glass or River-worn Pebble style)
Silicon Dioxide (SiO2)
Obsidian (likely black volcanic glass)
Obsidian; silica-rich, noncrystalline volcanic glass, typically rhyolitic (approximately 70–75% SiO₂)
Polished black obsidian
Volcanic glass, predominantly rhyolitic silica (SiO₂)
Amber (Black)
Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)
Obsidian
Obsidian (Volcanic Glass)
Quartz Pebble (Sea Glass-like texture)
Silicon Dioxide (SiO2)
Obsidian
Volcanic Glass (Amorphous Silica)
Obsidian
Volcanic glass
Pumice
Vesicular Rhyolite / Pumice
Tumbled mahogany obsidian
Volcanic glass; primarily SiO₂ with iron-oxide-rich brown inclusions
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with inclusions of Hematite or Magnetite)
Obsidian
Volcanic Glass (felsic composition)
Mahogany Obsidian
Volcanic glass containing Magnetite/Hematite
Polished black obsidian
Volcanic glass; primarily silica-rich rhyolitic composition (approximately 70–80% SiO₂)
Obsidian
Obsidian (Volcanic Glass)
Obsidian (Black Obsidian)
Obsidian (Volcanic Glass)
Obsidian (likely snowflake-free black variety)
Volcanic glass; primarily SiO₂-rich rhyolitic composition
Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
Obsidian
Volcanic Glass (Amorphous SiO2)
Black obsidian
Volcanic glass; predominantly rhyolitic silica-rich melt (approximately 70–80% SiO₂), lacking crystalline structure
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Obsidian (volcanic glass), likely black obsidian
Rhyolitic volcanic glass; predominantly amorphous SiO₂
Tumbled black stone, likely black obsidian
Obsidian — natural volcanic glass, primarily SiO₂
Likely obsidian fragment
Volcanic glass, predominantly silica-rich rhyolitic composition (SiO₂-rich)
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)