Obsidian
Volcanic Glass (SiO2)
igneous
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Obsidian
Obsidian (principally SiO2 + MgO, Fe3O4)
igneous
Chakra Stone Bracelet (mixed gemstones)
Multi-mineral/Gemstone assembly (primarily Quartz variety beads)
mineral
Ironstone with Limonite/Goethite coating
Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O)
sedimentary
Common Opal
Hydrated silica (SiO2 " nH2O)
mineral
Fossilized Shell in Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Ambergris
Ambrein (C30H52O)
mineraloid / organic geological substance
Slag (Industrial By-product)
Anthropogenic Vitreous Silica/Iron Silicate
mineral
Chrysocolla
Chrysocolla, (Cu, Al)2H2Si2O5(OH)4·nH2O
mineral
Limonite (Iron Ore)
Limonite (unstructured hydrated iron(III) oxide-hydroxides, often FeO(OH)·nH2O)
mineral
Chrysocolla in Cuprite (Sonora Sunrise)
Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O) with Cu2O
mineral
Amber
Succinite (Resinous fossilized tree sap)
Mineraloid
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Organic Gemstone (often associated with Sedimentary sequences)
White Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Iron Gossan (Limonite/Goethite)
Hydrated Iron Oxides (FeO(OH)·nH2O) from oxidation zones
sedimentary
Precious Opal
Hydrated Silica (SiO2·nH2O)
mineral
Vesicular Basalt with Opal or Quartz
Vesicular Basalt (Amorphous SiO2.nH2O if Opal)
igneous
Sea Glass (White/Clear)
Amorphous Silica (Alkali-Lime-Silica Glass), SiO2 + Na2O + CaO
Anthropogenic (Man-made product subject to geological processes)
Snowflake Obsidian
Obsidian with Cristobalite inclusions (Amorphous SiO2 + SiO2 inclusions)
igneous
Apache Tear (Obsidian)
Obsidian (Hydrated Amorphous Silica, SiO2 + MgO/Fe3O4)
igneous
Ferruginous Slag (Iron Smelting Byproduct)
Fused Silicate Scoria (Amorphous mixture of FeO, SiO2, and CaO)
Antropogenic Glass / Mineraloid
Obsidian (Apache Tear)
Obsidian (Amorphous Volcanic Glass / SiO2 with impurities)
igneous
Obsidian
Volcanic glass (SiO2-rich amorphous silicate)
igneous
Sea Glass (Turquoise/Aqua)
Amorphous Silica (SiO2) with transition metal dopants
Anthropogenic (Man-made material processed by nature)
Blue Opal Inlay (Simulated/Lab-created)
Hydrated Amorphous Silica (SiO2·nH2O) with polymer resin
mineraloid
Ferro-silicate Slag
Industrial Vitrified Slag (High-silica amorphous glass)
Mineral byproduct (Anthropogenic)
Man-made Carved Stone (Scream Mask/Skull motif)
Carved Soapstone or Serpentine-rich rock
Anthropogenic (Man-made artifact)
Pumice
Vesicular Rhyolite or Andesite (Amorphous volcanic glass)
igneous
Mixed Tumbled Gemstones and River Rocks
Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)
Mixed (Igneous, Sedimentary, Metamorphic, and Minerals)
Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
igneous
Amber
Succinite (fossilized tree resin)
mineraloid
Amber
Succinite (fossilized resin)
mineraloid
Obsidian (worked into an arrowhead profile)
Obsidian (volcanic glass), primarily SiO2 (Silicon Dioxide)
igneous
Coquina
Coquina (Bioclastic Calcarenite)
sedimentary
Amber
Fossilized Resin (C10H16O)
mineral
Amber
Succinite (C10H16O)
Mineraloid (Organic)
Limonite (Yellow Ochre)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
mineral
Amber
Succinite (fossilized resin)
mineral
Anthracite Coal
Anthracite
metamorphic
Amber
Succinite (organic mineraloid); Chemical formula: C10H16O
mineral
Slag
Metallurgical by-product
Anthropogenic (Man-made material)