Black Obsidian
Obsidian (Volcanic Glass, SiO2+)
Category
Browse mineraloid (man made glass) specimens identified by the Rock Identifier community.
Black Obsidian
Obsidian (Volcanic Glass, SiO2+)
Tektite (Indochinite)
Impact Glass (SiO2 + Al2O3)
Obsidian (likely black obsidian)
Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)
Fulgurite
Liesegang (Fulgurite)
Sea Glass (often mistaken for Gemstones)
Amorphous Silica (SiO2) with trace additives
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Obsidian
Amorphous volcanic glass (primarily SiO2)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Black Obsidian
Volcanic Glass (SiO2)
Blue slag glass / industrial smelter slag
Man-made iron-rich silicate slag; composition variable, commonly Fe–Ca–Mg–Al silicates with glassy phases
Amber
Succinite
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Polished black obsidian
Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)
Obsidian (black volcanic glass), possibly slag or basalt
Obsidian; chiefly amorphous volcanic silica glass, approximately SiO₂-rich rhyolitic composition
Black Obsidian
Volcanic Glass (SiO2 + impurities like Fe3O4)
Libyan Desert Glass
Natural Silica Glass (SiO2 with minor iron and titanium)
Tektite (Indochinite)
Tektite (SiO2 + Al2O3)
Black Obsidian
Obsidian (Amorphous Silicon Dioxide)
Black obsidian
Volcanic glass; predominantly rhyolitic silica glass (approximately 70–80% SiO₂)
Amber
Succinite (Fossilized Tree Resin)
Tektite (Indochinite)
Tektite - High-silica amorphous glass (SiO2 + Al2O3)
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
Tumbled black obsidian (likely)
Volcanic glass; primarily rhyolitic silica glass (SiO₂-rich, amorphous)
Amber
Succinite (approximate formula C10H16O)
Gold Sheen Obsidian
Volcanic Glass (SiO2 + impurities)
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Green Opal or Yellow Opal
Hydrated Silica (SiO2·nH2O)
Fulgurite
Lechatelierite (Silica glass), typically SiO2
Tektite (Indochinite)
Tektite (High-silica natural glass)
Tektite (Indochinite)
Tektite (High-silica natural glass)
Tektite (Indochinite)
Tektite (High-silica impact glass)
Tektite
Tektite (high-silica natural glass)
Black Obsidian
Obsidian (Volcanic Glass)
Obsidian arrowhead
Volcanic glass; predominantly SiO₂, with minor feldspar, pyroxene, and iron oxides
Obsidian
Volcanic Glass (70-75% SiO2)
Amber
Succinates (C10H16O)
Slag (Industrial Glass)
Anthropogenic Amorphous Vitreous Silicate
Mahogany Obsidian
Volcanic Glass with Hematite inclusions
Polished black obsidian pyramid/block
Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)
Blue Goldstone
Synthetic glass with copper or cobalt/manganese inclusions