Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
Category
Browse organic mineraloid specimens identified by the Rock Identifier community.
Snowflake Obsidian
Hydrated Volcanic Glass (primarily SiO2) with Cristobalite inclusions
Obsidian
Volcanic Glass (SiO2)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Opal
Hydrated amorphous silica (SiO2·nH2O)
Common Opal
SiO2·nH2O
Pink Opal
Hydrated amorphous silica (SiO2·nH2O)
Green Opal or Yellow Opal
Hydrated Silica (SiO2·nH2O)
Green Opal
Hydrated amorphous silica (SiO2·nH2O) with inclusions
Cobalt Glass Slug (Man-made Glass)
Amorphous Silica with Cobalt Oxide (SiO2 + CoO)
Opalite
Synthetic Glass (Amorphized Silicon Dioxide)
Common Opal (Green Opal / Pistachio Opal)
Hydrated silica (SiO2·nH2O)
Cullet Glass (Slag)
Amorphous Silicon Dioxide (Man-made)
Tektite (Indochinite)
Impact Glass (SiO2 + Al2O3)
Slag (Industrial Glass)
Anthropogenic Amorphous Vitreous Silicate
Common Opal
SiO2·nH2O (Hydrated Silicon Dioxide)
Green Opal
Hydrated amorphous silica (SiO2·nH2O)
Pearl
Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin
Conch Pearl
Calcareous concretion (CaCO3)
Amber
Succinite (approximate formula C10H16O)
Tektite (Indochinite)
Tektite (SiO2 + Al2O3)
Sea Glass (Frosted Quartz/Glass)
Amorphous Silicon Dioxide (SiO2)
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Black Opal
Hydrated silica (SiO2·nH2O)
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
Amber
Succinite (C10H16O)
Common Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Fulgurite
Liesegang (Fulgurite)
Opal
Hydrated silica (SiO2·nH2O)
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Cullet Glass (Slag Glass)
Amorphous Silicon Dioxide (Industrial Man-made)
Amber (specifically Burmese Amber or Burmite)
Succiniferous fossil resin (C10H16O)
Fulgurite
Fulgurite (Lechatelierite-rich fused silica)
Ethiopian Opal (Welo Opal)
Hydrated Amorphous Silica (SiO2·nH2O)
Dragon's Breath (Mexican Opal Glass)
Artisan Foil Glass (SiO2 based)
Cobalt Blue Slag Glass
Amorphous Silicon Dioxide (anthropogenic) with Cobalt additives
Sea Glass (often mistaken for Gemstones)
Amorphous Silica (SiO2) with trace additives
Amber
Succinite (fossilized tree resin)
Black obsidian (likely)
Volcanic glass; primarily silica-rich, noncrystalline SiO₂ composition
Polished black stone, likely black obsidian
Obsidian (volcanic glass), primarily rhyolitic silica glass
Obsidian
Obsidian (volcanic glass), primarily SiO2 (silicon dioxide)
Obsidian
Volcanic glass (mainly SiO2 with inclusions)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)