Obsidian
Obsidian (volcanic glass, amorphous silica rich rock)
Igneous
Category
Man Made Alloy (Metallic)
Browse man made alloy (metallic) specimens identified by the Rock Identifier community.
Pyrite in Quartz
Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)
mineral
Arsenopyrite in Quartz Matrix
Arsenopyrite (FeAsS) with Quartz (SiO2)
mineral
Limonite (Iron Ore)
Hydrous Iron Oxide (goethite, lepidocrocite)
Mineral
BROWN GRANITE (likely 'Tan Brown' or similar)
Granite (specifically a variety rich in orthoclase feldspar, often with biotite and possibly hornblende)
igneous
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Mica Schist
Crystalline Schist (often containing Muscovite, Biotite, and Quartz)
metamorphic
Gold Ore in Matrix
Native Gold (Au) in Quartz/Host Rock
mineral
Hematite
Iron (III) Oxide, Fe2O3
Mineral
Native Copper in Basalt
Cuprum (with Host Basalt)
igneous
Gold Ore in Quartz
Auriferous Quartz (Au + SiO2)
igneous
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Flint variety)
Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2
sedimentary
Iron Ore (Limonite and Hematite)
Goethite/Limonite (FeO(OH)·nH2O) and Hematite (Fe2O3)
mineral
Mica Schist
Mica Schist (predominantly Muscovite or Biotite sheet silicates)
metamorphic
Schist (specifically Mica Schist)
Mica Schist
metamorphic
Blue Celestite (with Galena)
Strontium sulfate (SrSO4) and Lead sulfide (PbS)
mineral
Quartz with Mica inclusions (Gold-colored Mica)
Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (Phlogopite/Muscovite) inclusions
Mineral
Gold in Quartz
Hydrothermal Quartz with Native Gold (SiO2 with Au)
mineral
Crushed Limestone
Calcium Carbonate (CaCO3)
Sedimentary
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various metal oxide impurities
Man-made material (Anthro-lithic product)
Asphalt (Bituminous Concrete)
Bituminous mix / Anthropogenic conglomerate
man-made composite (lithified equivalent of sedimentary)
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Man-made Glass (Not a natural rock or mineral)
Chert (Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Gold-bearing Quartz with Pyrite
Quartz (SiO2) with Gold (Au) and Pyrite (FeS2)
mineral
Pyrite in Quartz
Iron Sulfide (FeS2) in Silicon Dioxide (SiO2)
mineral
Mica Schist
Mica Schist (primarily Muscovite and Biotite phyllosilicates)
metamorphic
Biotite (Mica)
Biotite - K(Mg,Fe)3AlSi3O10(F,OH)2
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Mineral (or mineraloid if microcrystalline)
Aquamarine
Beryl (Be3Al2Si6O18), specifically the blue-green variety
Mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Shungite
Carbonaceous rock (primarily amorphous carbon)
Mineraloid
Pyrite on Quartz (Fool's Gold in Quartz)
Iron Sulfide (FeS2) on Silicon Dioxide (SiO2)
mineral
Marble
Marble (metamorphosed limestone/dolostone). Predominantly composed of Calcite (CaCO3) for marble derived from limestone, or Dolomite (CaMg(CO3)2) for marble derived from dolostone.
Metamorphic Rock
Sunstone
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
mineral
Iron-Nickel Meteorite (Possible Chondrite or Oxidized Iron)
Siderite (Nickel-Iron) or Chondrite (Si/Fe composite)
igneous
Green Aventurine
Silicon Dioxide (Quartz) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)
metamorphic
Banded Iron Formation (BIF) / Tiger Iron variety
Banded Iron Formation (composed primarily of Magnetite Fe3O4, Hematite Fe2O3, and Chert/Quartz SiO2)
sedimentary
Pallasite Meteorite (likely Imilac or Brenham)
Stony-Iron Meteorite (Pallasite)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral