Sedimentary (Man Made)

Granite (Pegmatitic)

Phaneritic Felsic Igneous Rock

Sandstone

Arenite (composed mainly of SiO2)

Sandstone

Arenite

Dumortierite in Quartz

Dumortierite (Al6O3(BO3)(SiO4)3) with Quartz (SiO2)

Diamond

Carbon (C)

Quartzite

Quartzite (SiO2)

Diamond

Carbon (C)

Pallasite Meteorite

Pallasite (Stony-Iron Meteorite)

Calcite

Calcite (Calcium Carbonate, CaCO3)

Pearl (with Peridot)

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

Quartz

Quartz (SiO₂)

Chert or flint fragment

Microcrystalline quartz (SiO₂), likely silicified rock

Sandstone

Arenite (SiO2 principal)

Blue chalcedony cabochon (probable)

Chalcedony, cryptocrystalline quartz; silicon dioxide (SiO₂)

Chert (with Calcite layering)

Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3)

Diamond (Faceted)

Carbon (C)

Raw Diamond

Carbon (C)

Diamond (in jewelry setting)

Adamantine Carbon (C)

Sandstone

Arenite

Limestone

Calcium Carbonate (CaCO3)

Sandstone (with Moss/Lichen Growth)

Sandstone (Quartz Arenite / Lithic Arenite)

Sandstone

Arenite (general term for sandstone)

White Jade / White Chalcedony

Nephrite Jade (Ca2(Mg,Fe)5Si8O22(OH)2) or Chalcedony (SiO2)

Fancy Jasper

Chalcedony (cryptocrystalline quartz) with inclusions

Quartzite

Metamorphic Quartzite (SiO2)

Diamond

C (Native Carbon)

Diamond

Natural Diamond (Carbon, C)

Rounded river cobble, likely weathered sandstone or siltstone

Quartz-rich clastic sedimentary rock; exact identification requires a fresh surface and testing

Diamond (or Diamond Simulant)

Carbon (C)

Green Slag Glass

Amorphous Silica / Glassy Blast Furnace Slag

Diamond (Cut Gemstone)

Natural Carbon (C)

Diamond (as set in a metal alloy ring)

Diamond (Pure Carbon, C)

Sandstone

Arenite (primarily SiO2)

Pearls (likely freshwater cultured pearls)

Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin

Jasper (yellow/cream variety)

SiO₂ (Cryptocrystalline Quartz)

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Pearl (Biogenic Mineraloid)

Calcium carbonate (Aragonite) and Conchiolin, CaCO3

Sandstone

Arenite (SiO2 primarily)

Sandstone

Clastic sedimentary rock (primarily SiO2)

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

Quartz (SiO₂ - Silicon Dioxide)

Turquoise

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

Granodiorite with Quartz Veining

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