Black Obsidian
Volcanic Glass (predominantly SiO2, Silicon Dioxide)
igneous
Category
Mineraloid (Impact Glass)
Browse mineraloid (impact glass) specimens identified by the Rock Identifier community.
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Obsidian
Obsidian (volcanic glass)
Igneous
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
igneous
Obsidian
Volcanic glass (silica-rich rhyolitic melt; primarily SiO₂)
igneous
Opalite (Synthetic Moonstone/Opal)
Synthetic Silica Glass
mineraloid (synthetic)
Cullet (Slag Glass)
Amorphous Silica (SiO2) with various metal oxide colorants
mineraloid / anthropogenic
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)
igneous
Obsidian
Volcanic Glass (Amorphous silicon dioxide with trace impurities)
igneous
Man-made Glass (Tumbled/Shaped)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Mineraloid (synthetic)
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
mineral
Slag
Ferrous slag (by-product of iron smelting)
Mineraloid / Anthropogenic
Polished black stone egg, probably black obsidian
Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements
gemstone
Sea Glass
Amorphous Silica (SiO2) with various additives
Mineraloid (Anthropogenic)
Opalite
Synthetic Opalised Glass
mineraloid (synthetic)
Amber
Succinate (Succinite for Baltic varieties)
Organic Mineraloid
Slag (Industrial Glass Slag)
Amorphous Silica / Ferro-silicate Slag
mineraloid / anthropogenic
Amber
Succinite (fossilized resin)
Organic Mineraloid
Slag (Industrial Glass)
Artificial Vitreous Silicate
mineraloid (anthropogenic)
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
igneous
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
mineraloid (synthetic)
Amber
Succinite
Organic (Mineraloid)
Polymictic breccia, possibly volcanic breccia
Polymictic clastic breccia; likely a matrix-supported breccia containing lithic fragments, quartz, feldspar, and dark mafic minerals
sedimentary
Pearl (Imitation or Cultured)
Calcium Carbonate (Aragonite/Calcite) - CaCO3
Mineraloid (Organic)
Opalite
Man-made Glass (SiO2 + additives)
mineraloid (synthetic)
Amber
Succinite (specifically Baltic Amber) - Formula: C10H16O (approximate)
Organic Mineraloid
Red Sandstone
Clastic Sedimentary Mineraloid (predominantly Quartz grains with Iron Oxide cement)
sedimentary
Amber
Succinite
Organic Mineraloid
Opalite
Synthetic Glass, SiO2 base with metallic inclusions
mineraloid (synthetic)
Amber
Succinite (a Fossilized Tree Resin); Chemical formula is approximately C10H16O
Organic mineraloid
Goldstone (Brown)
Aventurine glass
mineraloid (man-made)
Pearl (Cultured or Natural)
Aragonite (CaCO3) with Conchiolin
Organic Mineraloid
Slag Glass (Cullet)
Amorphous Silica (man-made), primarily SiO2 with trace metal oxides
Mineraloid / Synthetic Glass
Amber
Succinite (specifically for Baltic amber; general formula C10H16O)
Mineraloid (Organic)
Ferruginous Slag (Iron Smelting Byproduct)
Fused Silicate Scoria (Amorphous mixture of FeO, SiO2, and CaO)
Antropogenic Glass / Mineraloid
Cobalt Blue Sea Glass
Amorphous Silica Glass (SiO2 + CoO)
mineraloid / anthropogenic material
Man-made Crystal (Lead Glass)
Lead oxide-doped Silica Glass (approx. SiO2 + PbO)
Mineraloid/Synthetic Material
Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)
Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)
mineraloid / industrial byproduct
Goldstone (Brown)
Aventurine Glass (Silicon Dioxide infused with Copper crystals)
mineraloid (man-made glass)
Green Slag
Anthropogenic Silicate Glass
Mineraloid (Industrial byproduct)
Goldstone
Aventurine glass (Synthetic glass with copper inclusions)
mineraloid / man-made glass
Red Slag Glass
Amorphous Silica (Industrial byproduct with metallic oxide dopants)
Mineraloid / Industrial Byproduct
Glass Nugget (Tumbled Glass)
Amorphous Silicon Dioxide (SiO2) with additives
mineraloid (man-made)