Obsidian
Volcanic Glass (Amorphous SiO2)
Category
Browse man made alloy (metallic) specimens identified by the Rock Identifier community.
Obsidian
Volcanic Glass (Amorphous SiO2)
Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')
Calcite (Calcium Carbonate, CaCO3)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Grey Granite
Phaneritic Felsic Intrusive Igneous Rock
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
Pearl (Biogenic)
Nacre / Calcium Carbonate (CaCO3)
Diamond
Carbon (C)
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Granite
Phaneritic Igneous Rock (composed mostly of Quartz, Alkali Feldspar, and Plagioclase)
Granite
Phaneritic plutonic rock (SiO2 typically >69%)
Hematite
Iron(III) oxide (Fe2O3)
Hematite
Iron(III) oxide (Fe2O3)
Specular Hematite
Hematite (Fe2O3)
Peacock Ore (Bornite or Chalcopyrite treated with acid)
Bornite (Cu5FeS4) or Acid-washed Chalcopyrite (CuFeS2)
Specular Hematite
Hematite (Fe2O3)
Gold Nugget
Native Gold (Au)
Hematite
Iron(III) oxide (Fe2O3)
Mica-rich Schist fragment
Mica Schist
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Hematite
Iron(III) oxide (Fe2O3)
Sunstone
Oligoclase (a plagioclase feldspar variant), (Na,Ca)(Al,Si)4O8
Nuummite
Orthoamphibole (mixture of Anthophyllite and Gedrite)
Gold-bearing Quartz
Native Gold (Au) in Quartz (SiO2) matrix
Nobby Hematite (Iron Ore)
Hematite (Fe2O3)
Smoky Quartz with Siderite and Pyrite
Silicon Dioxide (SiO2) with Ferrous Carbonate (FeCO3) and Iron Sulfide (FeS2)
Hematite
Iron(III) oxide (Fe2O3)
Gold Nugget
Native Gold (Au)
Schist
Mica Schist (variety: Muscovite/Biotite Schist)
Hypersthene
Hypersthene (Magnesium Iron Silicate - (Mg,Fe)SiO3)
Hematite with Magnetite
Iron Oxide (Fe2O3)
Hematite
Iron(III) oxide (Fe2O3)
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Hematite (Iron Ore)
Hematite (alpha-Fe2O3)
Amethyst and Hematite Bracelet
Amethyst (SiO2) and Hematite (Fe2O3)
Slag (Industrial Byproduct)
Ferrous/Non-ferrous Silicate
Hematite
Hematite (Iron(III) oxide, Fe2O3)
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
Chert (specifically Flint or Common Chert node)
Silicon Dioxide (SiO2)
Chert (Jasper variety)
Silicon Dioxide (SiO2)
Diamond
Diamond (pure Carbon, C)