Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Category
Not A Natural Rock (Man Made Composite)
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Banded Calcite or Travertine
Calcium Carbonate (CaCO3)
Sedimentary
Smoky Quartz
Silicon Dioxide (SiO2) with trace aluminum and irradiation
mineral
Dark gray rounded stone, possibly basalt or slag
Uncertain; likely fine-grained basalt (plagioclase–pyroxene) or iron-rich industrial slag
igneous
Coquina
Biogenic Limestone (Calcite/Aragonite base, CaCO3)
sedimentary
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Slate
Metamorphic Pelitic Rock
metamorphic
Banded Gneiss
Gneiss (Foliated Metamorphic Rock)
metamorphic
Slate
Metamorphic Pelitic Rock
metamorphic
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Green Slag Glass
Amorphous Silica / Glassy Blast Furnace Slag
Mineraloid (Industrial byproduct)
Sandstone
Arenite (mostly SiO2)
sedimentary
Sandstone
Sedimentary Clastic Rock
sedimentary
Smoky Quartz (Faceted)
Silicon Dioxide (SiO2)
gemstone
Blue Dyed Agate
Silicon Dioxide (SiO2) with artificial pigment
gemstone
Sandstone
Arenite (SiO2 based)
sedimentary
Blue-beaded gemstone jewelry, likely lapis lazuli or dyed blue agate
Uncertain from the image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or blue chalcedony (SiO₂)
gemstone
Rock Specimen
Unclassified rock specimen
sedimentary
Jasper Marble
Silicon Dioxide (SiO2) with Impurities
sedimentary
Crushed Stone / Gravel
Aggregatus saxum (variable mineral composition)
sedimentary
Chert
Silicon dioxide (SiO2)
Sedimentary
Sandstone (with potential Arkose/Lithic characteristics)
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Ferrous Slag (Iron Smelting By-product)
Fused Siliceous Slag
Anthropogenic Material (Man-made Rock)
Fossil Coral
Scleractinia (Stony Coral) fossil
fossil
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Granodiorite
Granodiorite (phaneritic intrusive igneous rock)
igneous
Crackled Quartz (Blue Dyed)
Silicon Dioxide (SiO2) with anthropogenic dye
mineral
Sandstone
Arenite (SiO2 based clastic rock)
sedimentary
Sandstone
Clastic Sedimentary Rock
sedimentary
Chert (Flint/Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Angel Aura Quartz (Treated Clear Quartz)
Silicon Dioxide (SiO2) coated with Vaporized Silver and Platinum
mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2 + Fe4+ impurities)
mineral
Pearl
Calcium Carbonate (CaCO3) with Conchiolin
mineral
Granite
Phaneritic plutonic felsic rock
igneous
Chert
Chert (Microcrystalline Quartz)
sedimentary
Quartzite
Metamorphic Rock (Mainly SiO2)
metamorphic
Sandstone
Sandstone (Sedimentary rock composed of silicate grains)
sedimentary
Turquoise bead bracelet
Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
mineral
Chert (Flint)
Silicon dioxide (SiO2)
sedimentary
Goldstone and Aura Quartz
Cuprous Glass (Goldstone) and Titanium-coated SiO2 (Aura Quartz)
Mineral/Glass Specimen
Diamond (Faceted)
Carbon (C)
gemstone
Sandstone
Arenite (SiO2 based)
sedimentary