Granite
Granite (a plutonic rock)
Igneous
Category
Anthropogenic Specimen (Man Made Material)
Browse anthropogenic specimen (man made material) specimens identified by the Rock Identifier community.
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Coquina
Biogenic Limestone (Calcite/Aragonite base, CaCO3)
sedimentary
Banded Calcite (often commercially sold as 'Mexican Onyx' or 'Honey Onyx')
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Tumbled or rough turquoise-like specimen
Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O; identification is uncertain from the image
mineral
Pyrite in Matrix
Iron Sulfide (FeS2)
mineral
Blue-dyed Quartz Druzy
Silicon Dioxide (SiO2) with artificial pigment
mineral
Tumbled brown pebble
Indeterminate; likely quartz-rich sandstone or chert
sedimentary
Weathered quartz-rich sandstone or granitic rock
Indeterminate; likely iron-stained quartz sandstone, possibly weathered granite
sedimentary
Granite
Granite (phaneritic felsic intrusive rock)
igneous
Quartz geode (likely amethyst-bearing geode)
Microcrystalline quartz and drusy quartz; SiO₂, with possible iron-stained or amethyst quartz
mineral
Weathered gray metamorphic rock, likely phyllite or slate
Micaceous quartz–phyllosilicate rock; commonly quartz + muscovite/illite ± chlorite
metamorphic
Sandstone
Arenite (siliciclastic sedimentary rock composed mostly of quartz)
sedimentary
Marble
Recrystallized Calcite (CaCO3)
metamorphic
Diamond (Faceted)
Carbon (C)
gemstone
Fossiliferous Chert (with Fossil Shells)
Silicon Dioxide (SiO2) with biogenic inclusions
sedimentary
Vesicular volcanic rock, likely weathered scoria
Scoria (vesicular basaltic-andesitic volcanic rock), composition approximately plagioclase, pyroxene, and volcanic glass
igneous
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
mineral
Granite (Pegmatitic)
Phaneritic Felsic Igneous Rock
igneous
Chert (with potential fossil inclusion)
Microcrystalline Quartz (SiO2)
sedimentary
Diamond (or Diamond Simulant)
Carbon (C)
mineral
Sandstone
Arenite (SiO2 principal)
sedimentary
Chrysocolla in Malachite
Cu2CO3(OH)2 (Malachite) / Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla)
mineral
Ferro-Manganese Slag
Vitreous Silicate Slag
Anthropogenic (Industrial byproduct)
Pearl
Pearl (Calcium Carbonate with organic conchiolin, CaCO3)
mineral
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Quartz Pebble with Drusy/Crystalline Pocket
Silicon Dioxide (SiO2)
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Diamond
Carbon (C)
gemstone
Diamond
Carbon (C)
gemstone
Common Marble
Calcium Carbonate (CaCO3)
metamorphic
Milky quartz-bearing rock, possibly quartzite
Quartz (SiO₂), likely in a quartzite or quartz-rich metamorphic matrix
metamorphic
Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')
Calcite (Calcium Carbonate, CaCO3)
Sedimentary
Banded iron formation fragment (likely hematite–magnetite ironstone)
Banded iron formation; chiefly hematite (Fe₂O₃), magnetite (Fe₃O₄), and microcrystalline quartz (SiO₂)
sedimentary
Diorite
Diorite (intermediate intrusive igneous rock)
igneous
Diamond (in a cluster setting)
Crystallized Carbon (C)
mineral
Chert (Nodule)
Cryptocrystalline Quartz (SiO2)
sedimentary
Diamond
Carbon (C)
gemstone
Goldstone
Avventurina (Cu + SiO2 glass)
mineral
Greenstone / serpentinite carving
Serpentinite, chiefly serpentine-group minerals (antigorite, lizardite, or chrysotile); exact identification requires testing
metamorphic
Tektite (Indochinite)
Tektite (High-silica impact glass)
igneous
Basalt
Basalt
igneous
Tumbled blue-gray mineral specimen
Indeterminate; possibly dumortierite quartz, sodalite, or dyed stone
mineral