Obsidian (Black)
Obsidian (High-silica volcanic glass)
igneous
Category
Industrial Byproduct (Often Mistaken For Obsidian Or Mineral)
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
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Mahogany Obsidian
Obsidian (SiO2 + Fe2O3)
igneous
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
mineral
Chrysoprase
Silicon Dioxide (Nickel-bearing Chalcedony) - SiO2
mineral
Limestone with Lichen
Calcium Carbonate (CaCO3) with Endolithic/Epilithic Lichen
sedimentary
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
sedimentary
Ironstone Concretion
Ferruginous Sandstone / Siderite Concretion
sedimentary
Spinel
Magnesium aluminum oxide (MgAl2O4)
gemstone
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Quartz with Chalcopyrite
Silicon Dioxide (SiO2) with Copper Iron Sulfide (CuFeS2)
mineral
Black Onyx
Silicon Dioxide (SiO2)
mineral
Dalmatian Jasper
Peralkaline Rhyolite (composed of Quartz, Feldspar, and Arfvedsonite)
igneous
Obsidian (Blue)
Volcanic Glass (SiO2)
igneous
Ironstone concretion / Limonitic Sandstone
Goethite/Hematite Cemented Sandstone (Hydrated Iron Oxide)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Snowflake Obsidian
Spherulitic Volcanic Glass (SiO2 + impurities)
igneous
Blue Apatite
Apatite group (Ca5(PO4)3(F,Cl,OH))
mineral
Liesegang Banded Sandstone (Wonderstone)
Ferruginous Sandstone with Liesegang Rings
sedimentary
Blue Quartz (specifically Dumortierite Quartzite)
Silicon Dioxide (SiO2) with inclusions of Dumortierite (Al7BO3(SiO4)3O3)
metamorphic
Green Aventurine
Silicon dioxide (SiO2) with inclusions of Fuchsite mica
metamorphic
Snowflake Obsidian
Obsidian with Cristobalite inclusions (mostly amorphous SiO2)
igneous
Green Aventurine (Green Quartzite)
Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2(AlSi3O10)(OH)2)
metamorphic
Jasper with Manganese Dendrites
Silicon Dioxide (SiO2) with Oxide Mineral Inclusions
sedimentary
Pyrite in Shale
Iron Sulfide (FeS2)
mineral
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)
igneous
Fossilized Nut / Coprolite / Concretion
Trace Fossil / Permineralized Plant Material
fossil
Pyrite
Iron Sulfide (FeS2)
mineral
Specular Hematite (Specularite)
Iron Oxide (Fe2O3)
mineral
Fossil Brachiopod
Phylum Brachiopoda
fossil
Scoria (Basaltic Lava Rock)
Vesicular Basalt
igneous
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Green Sheen Obsidian
Volcanic Glass (SiO2 with microscopic inclusions)
igneous
Ferruginous Quartz
Silicon Dioxide (SiO2) with iron oxide inclusions
mineral
Obsidian
Volcanic Glass (Primary composition: SiO2 - Silicon Dioxide)
Igneous
Black Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Obsidian
Volcanic Glass (SiO2)
igneous
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Scoria (with likely iron oxidation)
Scoria (Basaltic Scoria)
igneous
Polished black stone, possibly basalt or black jasper
Basalt (fine-grained mafic rock) or microcrystalline quartz if jasper
igneous
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
igneous
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
metamorphic