Black Obsidian (Faceted)
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
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Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various additives
Man-made material (Anthropogenic 'mineraloid')
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Mineral
Green Slag Glass
Amorphous Silicon Dioxide (with metallic impurities)
Igneous (Anthropogenic)
Obsidian (Apache Tear)
Amorphous Volcanic Glass (SiO2 + impurities)
igneous
Green Slag Glass (Cullet)
Amorphous Silica (Industrial Glass Byproduct)
Synthetic/Byproduct (Non-igneous, non-sedimentary, non-metamorphic)
Faceted Glass (Costume Jewelry)
Amorphous Silicon Dioxide with colorants (Glass)
Synthetic/Man-made Material
Opalite
Synthetic Opalised Glass
mineral
Limonite with Quartz
Hydrated Iron Oxide Hydroxide, FeO(OH)·nH₂O with SiO₂
mineral
Petrified Wood
Silicified wood (Quartz/Chalcedony replacement)
fossil
Anthracite Coal
Anthracite
sedimentary
Shiva's Eye
Operculum of Turbo shells (Calcium carbonate)
fossil
Bauxite
Aluminium ore (Hydrated aluminium oxides AlOx(OH)3-2x)
sedimentary
Sea Glass
Man-made silicate glass
sedimentary
Chalk
Sedimentary carbonate rock (Calcite, CaCO3)
sedimentary
Amber
Fossilized Tree Resin
gemstone
Limonite Geode / Ironstone Concretion
Hydrated Iron Oxide (FeO(OH)·nH2O)
sedimentary
Moldavite
Moldavite (Silica Glass with impurities)
tektite
Anthracite Coal
Anthracite
sedimentary
Ironstone Concretion
Ferruginous Concretion (Fe2O3·nH2O)
sedimentary
Black Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Mudstone/Siltstone with Liesegang Bands
Argillaceous Sedimentary Rock with Chemical Banding
sedimentary
Mahogany Obsidian
Volcanic glass (SiO2 with Fe2O3 inclusions)
igneous
Limonite Concretion
FeO(OH)qnH2O (Hydrated iron(III) oxide-hydroxide mixture)
sedimentary
Amber
Succinite (Fossilized Tree Resin)
gemstone
Black Obsidian
Volcanic Glass (SiO2 + MgO / Fe3O4)
igneous
Obsidian
Obsidian (volcanic glass)
igneous
Black Obsidian cabochon
Volcanic Glass (SiO2 + impurities)
igneous
Anthracite Coal
Anthracite (Carbon rank)
sedimentary
Amber
Succinite (Fossilized Tree Resin)
gemstone
Tektite (Indochinite)
Tektite (Natural silica glass)
meteorite
Obsidian
Volcanic Glass (70% or more SiO2)
igneous
Black Obsidian
Volcanic Glass (Silicon Dioxide with impurities)
igneous
Amber
Succinite (approximate formula C10H16O)
mineral
Gossan (Iron Hat)
Hydrous Iron Oxides (predominantly Goethite FeO(OH) and Limonite)
mineral
Iron Slag (Industrial Byproduct)
Anthropogenic pyrometallurgical residue
mineral
Opalite
Man-made synthetic glass with opalescent effects (SiO2 + metal oxides)
mineraloid
Obsidian
Volcanic Glass (70% or more SiO2)
igneous
Fossil Crab
Decapoda (likely Avitelmessus or Raninidae family)
sedimentary
Snowflake Obsidian
Obsidian with Cristobalite inclusions
igneous
River Rock (Quartz-dominated)
Silicon Dioxide (SiO2) mixture with varied clastic sediments
sedimentary (alluvial deposit)