Magnetite (Lodestone)
Iron(II,III) oxide (Fe3O4)
mineral
Category
Mineral (Biogenic)
Browse mineral (biogenic) specimens identified by the Rock Identifier community.
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Ruby (Raw Corundum)
Al2O3 (Aluminum Oxide)
mineral
Rhodochrosite
Manganese Carbonate (MnCO3)
mineral
Sandstone
Sandstone (composed primarily of sand-sized minerals or rock grains)
sedimentary
Fluorite (Fluor-spar)
Calcium Fluoride (CaF2)
mineral
Fluorite with Quartz
Fluorite (CaF2) and Quartz (SiO2)
mineral
Chalcopyrite
Copper Iron Sulfide (CuFeS2)
mineral
Granite
Granite
Igneous
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Marble
Recrystallized Calcite (CaCO3)
metamorphic
Quartz in Limonite-rich Matrix
Silicon Dioxide (SiO2) with Goethite/Limonite FeO(OH)·nH2O
Mineral in Sedimentary/Secondary host
Rhodochrosite
Manganese Carbonate (MnCO3)
mineral
Granite
Phaneritic Felsic Igneous Rock
igneous
Fluorite (Rainbow, Purple-Blue Tumbled)
Calcium Fluoride (CaF2)
Mineral
Quartz (Clear Quartz/Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Black Sand (Magnetite/Heavy Mineral Concentrate)
Magnetite-rich Placers (Fe3O4)
sedimentary
Tumbled Mixed Gemstones and Rocks
Various mineral species including quartz (SiO2) and silicate minerals
mineral
Blue apatite specimen
Apatite-group mineral, commonly fluorapatite (Ca₅(PO₄)₃F)
mineral
Fluorite
Calcium fluoride (CaF2)
mineral
Raw greenish-blue quartz-bearing mineral specimen
Likely fluorite or chalcedony/quartz; exact identification requires hardness and crystal tests
mineral
Granite
Intrusive Igneous Rock
igneous
Amygdaloidal Basalt
Amygdaloidal Basalt (containing quartz/agate or zeolite fill)
igneous
Schist
Mica Schist
metamorphic
Quartz Vein in Hematitic Siltstone
Hydrothermal Quartz (SiO2) in Ferriferous Matrix
metamorphic
Pyrite
Iron Sulfide (FeS2)
mineral
Limonite
FeO(OH)·nH2O
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Mica Schist or Muscovite
KAl2(AlSi3O10)(OH)2
metamorphic
Limonite with Gossan / Iron Ore
Hydrated iron oxide-hydroxide, approximately FeO(OH)·nH2O
mineral
Graphite
Graphite (Carbon, C)
mineral
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(F,OH)2)
mineral
Specular Hematite
Hematite (Fe2O3)
mineral
Ironstone / Hematite
Iron(III) oxide (Fe2O3)
mineral
Celestite
Celestine (SrSO4)
mineral
Graphite
Graphite (Carbon, C)
mineral
Galena with Pyrite
Lead Sulfide (PbS) associated with Iron Sulfide (FeS2)
mineral
Feldspar
Triclinic or Monoclinic Tectosilicate (e.g., KAlSi3O8)
mineral
Chalcopyrite
CuFeS2
mineral
Hematite
Hematite (Fe2O3)
mineral
Muscovite
KAl2(AlSi3O10)(OH)2
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Quartz Crystal
Silicon Dioxide (SiO2)
mineral