Tektite (likely Australite)
Tektite (no specific chemical formula as it's a natural glass of variable composition, mostly SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O, TiO2)
Mineral (specifically a mineraloid)
Category
Mineral (Specifically A Mineraloid)
Browse mineral (specifically a mineraloid) specimens identified by the Rock Identifier community.
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Jet
Lignite (Anthracite-grade compact coal)
sedimentary
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
igneous
Mahogany Obsidian
Volcanic Glass with Hematite inclusions
igneous
Bumblebee Jasper
Anhydrite-Aragonite mixture with Orpiment and Realgar
mineraloid
Mahogany Obsidian
Obsidian (Volcanic Glass with Hematite/Magnetite inclusions), SiO2
igneous
Obsidian (specifically Mahogany Obsidian)
Volcanic glass (high silica content, SiO2)
igneous
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Mineraloid
Mahogany Obsidian
Volcanic glass (Silicon Dioxide with Hematite/Magnetite inclusions)
igneous
Shungite
Shungite (carbon-rich Precambrian mineraloid)
mineral
Mahogany Obsidian
Obsidian (SiO2 + Fe2O3)
igneous
Opalite
Synthetic Glass (Silica-based)
gemstone
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
igneous
Fire Opal (in Matrix)
Hydrated Silica (SiO2·nH2O)
mineral
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Mineraloid
Snowflake Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with Cristobalite inclusions)
igneous
Amber
Succinite (specifically for Baltic amber); approximate formula C10H16O
Mineraloid
Amber (Black)
Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)
Mineraloid
Amber
Succinite
Mineraloid
Black Pearl (Tahitian Type)
Aragonite / Conchiolin composite (CaCO3)
mineraloid
Dragon's Breath (Mexican Opal Glass)
Artisan Foil Glass (SiO2 based)
mineraloid
Black Pearl (Tahitian or Irradiated Type)
Organic gemstone (Calcium Carbonate with Conchiolin Binding)
mineraloid
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
mineral
Amber
Succinite (fossilized tree resin)
Organic Mineraloid
Amber (specifically Burmese Amber or Burmite)
Succiniferous fossil resin (C10H16O)
mineraloid
Amber
Succinite (specifically for Baltic amber); chemical formula approximately C10H16O
Mineraloid
Amber (Burmite)
Fossilized tree resin (Succinite variant)
Organic mineraloid
Obsidian
Volcanic glass (SiO2 + impurities)
igneous
Amber (specifically Red or Cherry Amber)
Succinite (Resinite); Chemical formula: C10H16O
Mineraloid
Amber
Succinite (specifically Baltic Amber) - Formula: C10H16O (approximate)
Organic Mineraloid
Amber
Succinite (specifically for Baltic amber); approximate formula C10H16O
organic mineraloid
Limonite or Ironstone Nodule
FeO(OH)·nH2O (Hydrated iron(III) oxide-hydroxide)
sedimentary
Black Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Black Obsidian
Volcanic Glass (Amorphous SiO2 with trace impurities)
igneous
Amber
Succinite (Organic Mineraloid)
mineral
Mahogany Obsidian Arrowhead
Volcanic Glass with Hematite/Magnetite inclusions (Amorphous Silicon Dioxide)
igneous
Black Obsidian
Volcanic glass
igneous
Obsidian
Volcanic Glass
igneous
Obsidian
Volcanic Glass (Amorphous silicon dioxide with impurities)
igneous
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Igneous
Gold Sheen Obsidian
Volcanic Glass (SiO2 + Fe3O4 / Gas Inclusions)
igneous