Calcite
Calcite (Mineral; CaCO₃)
Mineral
Category
Mineral (Extraterrestrial)
Browse mineral (extraterrestrial) specimens identified by the Rock Identifier community.
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Chrysocolla
Hydrated copper silicate (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Quartz-rich gneiss (probable banded metamorphic rock)
Gneiss; composition chiefly quartz, feldspar, and mica, possibly with amphibole
metamorphic
Small pink mineral fragment
Indeterminate; possibly rose quartz or feldspar
mineral
River Stones (Quartzite and Sandstone)
Quartzite / Sedimentary Rock (SiO2 dominant)
sedimentary
Ironstone concretion (possibly pyrite-bearing)
Iron-rich sedimentary concretion, likely composed of goethite/limonite with possible pyrite
sedimentary
Likely pegmatite with quartz and mica
Granitic pegmatite, chiefly quartz (SiO₂), feldspar, and mica
igneous
Tumbled amethyst
Quartz, SiO₂; purple color typically from trace iron and natural irradiation
gemstone
Purple druzy quartz (likely dyed or coated)
Quartz, SiO₂ (trigonal crystal system)
mineral
Tumbled amethyst
Quartz, SiO₂; purple coloration from trace iron and natural irradiation
mineral
Amethyst (likely tumbled or polished)
Quartz, SiO₂; purple color commonly caused by trace iron and natural irradiation
mineral
Yellow Quartz
Silicon Dioxide (SiO2)
mineral
Polished orbicular jasper (likely ocean jasper)
Silica-rich microcrystalline quartz/chalcedony with iron oxides and accessory minerals; SiO₂-dominant
mineral
Limonite / Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O)
mineral
Vein-bearing metamorphic rock, likely gneiss or schist
Banded silicate rock; likely quartz–feldspar–mica gneiss with a quartz vein
metamorphic
Weathered basalt pebble
Basalt, a fine-grained mafic volcanic rock; likely olivine- and pyroxene-bearing
igneous
Vesicular basalt (likely weathered lava rock)
Vesicular basalt; primarily plagioclase feldspar, pyroxene, and volcanic glass, with possible iron-oxide alteration
igneous
Granite (likely a granitic rock)
Granite, composed chiefly of quartz, feldspar, and dark mica or amphibole
igneous
Likely amphibolite
Amphibolite, composed mainly of hornblende (amphibole) and plagioclase feldspar
metamorphic
Green-speckled igneous rock, likely epidote-bearing basalt or serpentinite
Tentatively epidote-bearing basalt (compositionally uncertain from the image)
igneous
Shark Tooth Fossil
Carcharocles megalodon or similar extinct shark tooth
fossil
Snowflake Obsidian
Obsidian with Cristobalite inclusions
igneous
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Milky quartz fragment
Quartz, silicon dioxide (SiO₂)
mineral
Blue Apatite
Apatite (Ca5(PO4)3(F,Cl,OH))
mineral
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
mineral
Fluorite
Calcium fluoride (CaF2)
mineral
Malachite and Azurite on Gossan (Ironstone Matrix)
Cu2CO3(OH)2 (Malachite) on FeO(OH)·nH2O (Limonite/Gossan)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Small unidentified mineral specimen
Indeterminate from image; possibly a quartz-family crystal or sulfide mineral
mineral
Gneiss
Metamorphic Foliated Gneiss
metamorphic
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Schist
Schist; commonly mica schist, composed chiefly of muscovite/biotite mica with quartz and feldspar
metamorphic
Chrysocolla
Hydrated copper silicate - Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O
mineral
Quartz-rich pegmatite (likely mica-bearing granite)
Granitic pegmatite; chiefly quartz (SiO₂), feldspar, and mica (muscovite/biotite)
igneous
Sandstone
Clastic Sedimentary Rock
sedimentary
Note regarding baguette production (not a rock)
Digital text image - Somali language
not a rock
Banded Gneiss Pebble
Gneiss (Metamorphic Rock)
metamorphic
Likely gneiss pebble
Gneiss, a foliated metamorphic rock composed mainly of quartz, feldspar, and mica
metamorphic
Granite pebble
Granite, chiefly quartz, feldspar, and mica
igneous