Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Category
Mineral (Man Made Composite)
Browse mineral (man made composite) specimens identified by the Rock Identifier community.
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Banded Calcite (often commercially sold as 'Mexican Onyx' or 'Honey Onyx')
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Fossilized oyster shell
Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite
fossil
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Slate
Metamorphic Pelitic Rock
metamorphic
Banded malachite cabochon
Malachite, Cu₂CO₃(OH)₂; the dark bands may be manganese-oxide or other sulfide-rich matrix, and could also indicate a composite or treated specimen
mineral
Ruby in Zoisite
Anyolite (composite of Corundum Al2O3 and Zoisite Ca2Al3(SiO4)(Si2O7)O(OH))
metamorphic
Fossilized Shark Tooth (Sand Tiger)
Carcharias sp. (Fossilized Tooth)
fossil
Pyrite
Iron Sulfide (FeS2)
mineral
Tumbled greenstone (likely serpentinite or green jasper)
Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing
metamorphic
Coal (Anthracite / Bituminous)
Organic Sedimentary Rock (Carbon-based)
sedimentary
Diamond in Kimberlite
Diamond (C in Kimberlite Matrix)
igneous
Flint/Chert Nodule in Limestone
Sedimentary rock containing microcrystalline quartz (SiO2) within a calcium carbonate (CaCO3) matrix
sedimentary
Jasper
Silicon Dioxide (SiO2)
sedimentary
Coquina
Biogenic Limestone (Calcite/Aragonite base, CaCO3)
sedimentary
Amber
Succinite (Carbon-based organic compound; approximate formula C10H16O)
Mineraloid
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite in Matrix
Iron Sulfide (FeS2)
mineral
Blue Goldstone
Aventurine Glass (Silicon Dioxide with metal inclusions)
man-made glass mineral simulant
Exposed aggregate concrete (stone-chip surface)
Portland-cement concrete containing natural aggregate; not a natural rock
sedimentary
Slate
Foliated Metamorphic Slate
metamorphic
Diamond
Diamond (pure Carbon, C)
mineral
Turquoise bead bracelet
Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
mineral
Diabase (Dolerite)
Diabase / Dolerite
igneous
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Antropogenic (Man-made industrial byproduct)
Diorite
Diorite
igneous
Sandstone
Arenite (SiO2 principal)
sedimentary
Land Snail Shell
Gastropoda (Calcium Carbonate, CaCO3)
fossil
Fossil coral fragment
Fossilized colonial coral, commonly *Hexagonaria* (often called Petoskey stone) or related scleractinian/tabulate coral
fossil
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
sedimentary
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Green Slag Glass
Cullet (Amorphous Silicon Dioxide with impurities)
Man-made rock-like material
Fossilized Coral (Coquina/Limestone)
Cnidaria Anthozoa (Fossilized)
sedimentary
Bituminous Coal (with Anthracite or Vitrinite inclusion)
Organic-rich Sedimentary Rock (Carboniferous classification)
sedimentary
![Turquoise (Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]) — mineral](https://media.rockidentification.com/92ebc6b5-08ac-4229-a727-57a096ec7f2c-thumbnail.jpg)
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Angel Aura Quartz (Treated Clear Quartz)
Silicon Dioxide (SiO2) coated with Vaporized Silver and Platinum
mineral
Basalt
Basalt
igneous
Blue-dyed Quartz Druzy
Silicon Dioxide (SiO2) with artificial pigment
mineral