Synthetic (Not A Natural Rock)

Browse synthetic (not a natural rock) specimens identified by the Rock Identifier community.

Turquoise

Hydrous phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

mineral

Turquoise and Red Coral

Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)

mineral

Halite

Halite (NaCl)

Mineral

Quartzite

Metamorphic

Sandstone

Sandstone (composed primarily of sand-sized minerals or rock grains)

sedimentary

Diamond

Diamond (Carbon, C)

mineral

Amber (Cherry or Red variety)

Succinite (with various trace amounts of organic compounds)

Organic Gemstone (not a rock)

Basalt with Weathered Surface

Basalt

Igneous

Aquamarine and clear quartz

Aquamarine (Be3Al2Si6O18), Quartz (SiO2)

Mineral

Quartz (likely a macrocrystalline variety like milky quartz or smoky quartz, given the appearance in the image)

Quartz (SiO₂ - Silicon Dioxide)

Mineral

Agate (specifically, multi-colored or pastel-dyed agate)

Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).

Mineral

Diamond

Diamond (carbon allotrope), C (chemical formula)

Mineral

Pink Stained Rock (Likely Quartzite or Sandstone with Iron Oxide Staining)

Quartzite (metamorphic) or Sandstone (sedimentary); coloration likely due to hematite or other iron oxides.

Metamorphic or Sedimentary (with staining)

K2 Azurite Granite / K2 Stone

Granite (igneous rock) with Azurite inclusions (mineral)

igneous

Diamond

Diamond (C)

Mineral

Smoky Quartz

SiO2 (Silicon Dioxide)

Mineral

Shungite

Carbonaceous rock (primarily amorphous carbon)

Mineraloid

Gold (Elemental Metal)

Gold (Au)

Mineral

Shale

Shale (fine-grained clastic sedimentary rock)

Sedimentary

Grey Slate

Foliated Metamorphic Rock (formed by low-grade regional metamorphism of shale or mudstone)

metamorphic

Sandstone (likely a river or beach pebble)

Sandstone (a clastic sedimentary rock)

Sedimentary Rock

Micaceous Rock (likely Muscovite Schist/Gneiss or a Muscovite-rich Specimen)

Predominantly Muscovite (KAl2(AlSi3O10)(F,OH)2), often found in rocks like Muscovite Schist or Muscovite Gneiss.

Metamorphic, Mineral (within a rock type)

Man-made earbud charging case (Not a rock or mineral)

Acrylonitrile Butadiene Styrene (ABS) Plastic with electronic components

Synthetic/Man-made object

Quartz (likely tumbled or naturally water-worn)

Quartz (SiO₂ - Silicon Dioxide)

Mineral

Black Obsidian

Obsidian, volcanic glass (Amorphous SiO₂)

Igneous Rock

Shale

sedimentary

Moldavite

Moldavite (Siliceous vitreous substance)

tektite (natural glass)

Chert / Flint

Chert (varieties include Flint)

Sedimentary

Agate (various color varieties)

SiO₂ (Silicon Dioxide)

Mineral (specifically a variety of Chalcedony, which is a microcrystalline quartz)

Quartz

Silicon dioxide (SiO₂)

Mineral

Beads (likely glass or man-made material)

N/A (artificial material)

Man-made material, not a natural rock or mineral specimen

Agate

Agate (a cryptocrystalline variety of Quartz, SiO₂)

Mineral

Coquina

Coquina (a type of limestone)

Sedimentary

Halite

Halite (Sodium Chloride - NaCl)

Mineral

Glauconitic Sandstone (or Greensand)

Glauconitic Siliciclastic Rock (Containing (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

sedimentary

Granite

Granite (a broadly defined plutonic igneous rock, often more specifically classified as quartz monzonite or granodiorite based on precise mineral percentages)

igneous