Polished mahogany obsidian (probable)
Volcanic glass; chiefly rhyolitic silica-rich glass (SiO₂), compositionally near rhyolite
Category
Browse mineraloid (man made glass) specimens identified by the Rock Identifier community.
Polished mahogany obsidian (probable)
Volcanic glass; chiefly rhyolitic silica-rich glass (SiO₂), compositionally near rhyolite
Black Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
Snowflake Obsidian
Volcanic Glass with Spherulite Inclusions (70-75% SiO2)
Amber with Inclusion
Succiniferous fossil resin (C10H16O)
Snowflake Obsidian
Obsidian with Spherulitic Cristobalite (SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Blue slag glass or dyed glass-like industrial material
Amorphous silicate glass; likely copper-bearing blue slag, but possibly colored man-made glass
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
Obsidian with Mahogany Phasing
Volcanic Glass (SiO2 + Fe2O3)
Mahogany Obsidian
Volcanic Glass with Hematite inclusions (SiO2 + Fe2O3)
Obsidian
Volcanic Glass (70% or more SiO2)
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
Obsidian
Obsidian (volcanic glass; primarily SiO2)
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Obsidian (Volcanic Glass)
Blue chalcedony cabochon (probable)
Chalcedony, a cryptocrystalline variety of quartz; silicon dioxide, SiO₂
Obsidian
Amorphous volcanic glass (SiO2)
Likely obsidian (possibly tektite or slag glass)
Volcanic glass; primarily SiO₂, noncrystalline
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Dyed Quartz Geode
Silicon Dioxide (SiO2) with artificial pigment
Slag Glass (Cullet)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Obsidian
Obsidian (Amorphous volcanic glass, predominantly SiO2)
Fulgurite
Luechatelierite (SiO2 glass)
Black Obsidian
Volcanic Glass (SiO2)
Obsidian
Volcanic Glass (SiO2)
Fulgurite
Liesegang (Fulgurite)
Sea Glass (often mistaken for Gemstones)
Amorphous Silica (SiO2) with trace additives
Amber
Succinite
Obsidian
Obsidian (Volcanic Glass)
Obsidian
Volcanic Glass (SiO2)
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Tektite (Indochinite)
Tektite (SiO2 + Al2O3)
Black Obsidian
Volcanic Glass (SiO2 + impurities like Fe3O4)
Mahogany Obsidian
Volcanic Glass with Hematite (SiO2 + Fe2O3)
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Black Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)