Red cabochon gemstone, likely carnelian or dyed chalcedony
Chalcedony (microcrystalline quartz), SiO₂; exact identification requires testing
gemstone
Category
Mineraloid (Impact Glass)
Browse mineraloid (impact glass) specimens identified by the Rock Identifier community.
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Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial byproduct)
mineraloid
Fulgurite
Luechatelierite (SiO2 glass)
mineraloid
Fulgurite
Liesegang (Fulgurite)
Mineraloid
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 with impurities)
igneous
Black Obsidian
Volcanic Glass (SiO2)
igneous
Obsidian
Volcanic Glass (SiO2)
igneous
Obsidian
Volcanic Glass (SiO2)
igneous
Amber
Succinite
Mineraloid
Obsidian
Obsidian (Volcanic Glass)
Igneous
Obsidian
Volcanic Glass (SiO2)
igneous
Smoky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
mineral
Obsidian
Obsidian (Amorphous volcanic glass, predominantly SiO2)
igneous
Obsidian
Obsidian (Extrusive Volcanic Glass)
igneous
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Snowflake Obsidian
Volcanic Glass with Spherulite inclusions (Chemical composition: 70–75% SiO2 + MgO, Fe3O4)
igneous
Black Obsidian
Obsidian (Volcanic Glass, SiO2+)
igneous
Black Obsidian
Volcanic Glass (SiO2 + impurities like Fe3O4)
igneous
Mahogany Obsidian
Volcanic Glass with Hematite (SiO2 + Fe2O3)
igneous
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Amber
Succinite (Fossilized Tree Resin)
mineraloid
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
igneous
Amber
Succinite (approximate formula C10H16O)
mineraloid
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
mineraloid
Black Obsidian
Volcanic Glass (SiO2)
igneous
Green Opal or Yellow Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Amber
Succinite (Carbon-based organic compound; approximate formula C10H16O)
Mineraloid
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Black Obsidian
Obsidian (Amorphous Silicon Dioxide)
igneous
Obsidian
Amorphous volcanic glass (SiO2)
igneous
Opalite
Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)
mineraloid
Obsidian
Amorphous volcanic glass (primarily SiO2)
igneous
Amber
Succinite (with approximate formula C10H16O)
mineraloid
Polished black obsidian pyramid/block
Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)
igneous
Opalite
Man-made opalescent glass
gemstone
Gold Sheen Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Opalite
Synthetic Glass (Amorphized Silicon Dioxide)
mineraloid
Snowflake Obsidian
Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)
igneous
Fulgurite
Lechatelierite (Silica glass), typically SiO2
mineraloid
Slag (Industrial Glass)
Anthropogenic Amorphous Vitreous Silicate
mineraloid
Amber
Succinates (C10H16O)
mineraloid
Fulgurite
Fulgurite (Lechatelierite-rich fused silica)
mineraloid