Snowflake Obsidian (Flower Jasper variant)
Vitreous volcanic silicate with cristobalite inclusions
igneous
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
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Ethiopian Opal (Welo Opal in Matrix)
Hydrated Silica (SiO2·nH2O)
mineral
Iron Slag
Iron smelting byproduct (Glassy/vesicular silicate)
anthropogenic / industrial byproduct
Coal (Bituminous)
Bituminous Coal (C)
sedimentary
Limonitic Gossan
Goethite/Limonite aggregate after sulfide
igneous and metamorphic derivative (weathered)
Bituminous Coal
Humic coal (Carboniferous fossil fuel)
sedimentary
Amber
Succinite (fossilized tree resin)
mineral
Acrylic or Resin (Synthetic Imitation)
Polymethyl Methacrylate (PMMA) or Polyepoxide
Synthetic/Man-made Polymer
Ferrochrome Slag
Anthropogenic slag (Fe-Cr alloy waste)
industrial byproduct
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Sandstone Concretion
Moqui Marble (Iron-oxide concretion)
sedimentary
Obsidian
Obsidian (Volcanic Glass)
igneous
Obsidian
Obsidian (principally SiO2)
igneous
Pumice
Pumice (a highly vesicular volcanic rock)
igneous
Snowflake Obsidian
Vitreous volcanic silicate rock (SiO2) with Spherulite inclusions
igneous
Amber
Succinite (fossilized resin); C10H16O
mineraloid
Obsidian
Obsidian (Volcanic glass), SiO2 (70% or more)
igneous
Dendritic Siltstone
Siltstone with Manganese Dendrites (MnO2)
sedimentary
Pumice
Felsic Volcanic Glass / Vesicular Rhyolite
Igneous
Chrysocolla on Quartz with Iron Oxides
Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)
mineral
Obsidian
Obsidian (Volcanic Glass)
Igneous
Ironstone Concretion
Siderite or Goethite Concretion
sedimentary
Fossilized Shark Tooth
Fossil Chondrichthyes (various genera such as Carcharias or Odontaspis)
sedimentary
Limonite
Limonite (Hydrous iron oxides, FeO(OH)·nH2O)
mineral
Mahogany Obsidian
Volcanic Glass (SiO2 + Fe2O3)
igneous
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Moqui Marble (Ironstone Concretion)
Iron Oxide Concretion (Fe2O3 / FeO(OH))
sedimentary
Amber
Succinite (with approximate formula C10H16O)
mineraloid
Man-made Slag (Industrial Byproduct)
Anthropogenic Glassy Residue
not a natural rock
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
sedimentary
Obsidian
Volcanic Glass (SiO2)
igneous
Opaline Glass (Opalite)
Synthetic Silicon Dioxide Glass
Mineraloid (Man-made)
Opal (Precious Opal)
Hydrated Silica (SiO2·nH2O)
mineral
Fire Opal (in matrix)
Hydrated Silica (SiO2·nH2O)
Mineraloid
Amber
Succinite (a Fossilized Tree Resin); Chemical formula is approximately C10H16O
Organic mineraloid
Amber / Copal
Succinite (fossilized resin)
mineraloid
Scoria (Volcanic Rock)
Scoria (often basaltic scoria)
Igneous
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Iron Slag
Anthropogenic pyrometallurgical residue
industrial byproduct
Obsidian
Volcanic Glass (Primary component: SiO2)
igneous
Libyan Desert Glass
Libyan Desert Glass (Impactite / High-silica Lechatelierite)
mineral
Mahogany Obsidian
Obsidian (volcanic glass with Hematite/Magnetite inclusions)
igneous