Anthropogenic (Man Made)

Likely gold-colored metal ring with a possible gemstone

Uncertain; possibly gold alloy (Au) with a small quartz or glass-like setting

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Quartzite

Quartzite (SiO2)

Diamond

Carbon (C)

Pearl (with Peridot)

Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4

Greenstone / serpentinite carving

Serpentinite, chiefly serpentine-group minerals (antigorite, lizardite, or chrysotile); exact identification requires testing

Chert (varieties: Flint or Jasper)

Silicon dioxide (SiO2) / Microcrystalline Quartz

Diamond (Faceted)

Carbon (C)

Raw Diamond

Carbon (C)

Diamond (in jewelry setting)

Adamantine Carbon (C)

Chert (Chocolate or Brown Flint)

Chert (SiO2)

Chert (Flint/Chalcedony)

Silicon Dioxide (SiO2)

Sandstone (Red/Brown Variety)

Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)

Flaked stone projectile point

Likely worked chert or fine-grained silicified shale; exact lithology cannot be confirmed from the image

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Quartzite

Metamorphic Quartzite (SiO2)

Pyrite

Iron Sulfide (FeS2)

Diamond

Natural Diamond (Carbon, C)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Diamond

C (Native Carbon)

Green-and-white terrazzo (likely serpentine/marble aggregate)

Composite decorative stone; probable serpentinite (Mg₃Si₂O₅(OH)₄) with white calcite marble fragments in cementitious matrix

Diamond (or Diamond Simulant)

Carbon (C)

Green Slag Glass

Amorphous Silica / Glassy Blast Furnace Slag

Sandstone

Arenite (SiO2 principal)

Rounded quartz pebble

Quartz (silicon dioxide, SiO₂)

Diamond (Cut Gemstone)

Natural Carbon (C)

Diamond (as set in a metal alloy ring)

Diamond (Pure Carbon, C)

Pearls (likely freshwater cultured pearls)

Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin

Swirled Agate Bead

Silicon Dioxide (SiO2)

Tumbled obsidian

Volcanic glass; chiefly SiO₂, noncrystalline

Red gemstone ring, likely garnet or synthetic ruby

Possibly almandine garnet (Fe₃Al₂(SiO₄)₃) or corundum/ruby (Al₂O₃); image alone cannot distinguish

Tumbled greenstone (likely serpentinite or green jasper)

Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing

Quartz (Microcrystalline/Chert)

Silicon Dioxide (SiO2)

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Carved serpentine pendant

Serpentine-group minerals, commonly antigorite/lizardite (Mg₃Si₂O₅(OH)₄), possibly mixed with chlorite or other inclusions

Pearl (Biogenic Mineraloid)

Calcium carbonate (Aragonite) and Conchiolin, CaCO3

Flint

Silicon Dioxide (SiO2) - Chert variety

Coquina / Fossiliferous Limestone

Fossiliferous Limestone (Calcite, CaCO3)

Granodiorite with Quartz Veining

Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins

Chert (variations include Flint/Novaculite)

Chert (formula: SiO2)

Chert (often called Flint for darker varieties)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz