Gemstone

Turquoise

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

Garnet (specifically Almandine)

Almandine (Fe3Al2(SiO4)3)

Amethyst

Crystalline Quartz (SiO2) with iron impurities

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Beryl (Aquamarine) in Matrix

Beryllium aluminum silicate (Be3Al2(SiO3)6)

Red Jasper

Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions

Chert (Commonly known as Jasper or Flint)

Microcrystalline Quartz (SiO2)

Garnet (almandine or pyrope variety)

Silicate mineral Group: (Fe, Mg, Mn, Ca)3(Al, Fe, Cr)2(SiO4)3

Amethyst Quartz (Amethyst Geode)

Silicon Dioxide (SiO2) with iron impurities

Labradorite (a variety of Anorthosite or Plagioclase)

Labradorite (member of Plagioclase Feldspar series), (Ca,Na)(Al,Si)4O8

Rose Quartz

Quartz (SiO₂), variety Rose Quartz

Jade (Nephrite or Jadeite)

Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2 (amphibole mineral); Jadeite: NaAlSi2O6 (pyroxene mineral)

Aquamarine

Beryl (Be3Al2Si6O18)

Green Aventurine

Aventurine Quartz (SiO2 + Fuchsite inclusions)

Kyanite (Blue Kyanite)

Kyanite (Al2SiO5)

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Chert (and/or Chalcedony)

Microcrystalline Silica (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Malachite

Copper carbonate hydroxide [Cu2CO3(OH)2]

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

Moonstone

Adularia (orthoclase) or Albite (plagioclase), a feldspar mineral (KAlSi3O8 or NaAlSi3O8 respectively, often a mixture)

Blue Sapphire (Ceylon)

Corundum (Al2O3) with traces of Iron and Titanium

Carnelian Agate/Jasper blend

Silicon Dioxide (SiO2) - variety of Chalcedony

Chert (variations include Flint/Novaculite)

Chert (formula: SiO2)

Jasper

Jasper (Silica/Silicon Dioxide, SiO2)

Chert (Arrowhead/Artifact Fragment)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pallasite Meteorite

Pallasite (Stony-iron meteorite; Fe-Ni alloy with (Mg,Fe)2SiO4 olivine)

Red Jasper

Jasper (Silicon Dioxide with Iron Oxide impurities), formula: SiO2

Carnelian

Silicon dioxide (SiO2) with Iron Oxide impurities (Fe2O3)

Jadeite

Jadeite (NaAlSi2O6)

Pyrite

Iron Sulfide (FeS2)

Rose Quartz

Silicon Dioxide (SiO2) with trace impurities of Titanium, Manganese, or Iron

Rough Dark Green Sapphire

Corundum (Al2O3)

Amazonite (Tumbled Chips)

Potassium Feldspar (KAlSi3O8)

Common Opal with Host Rock

Opal (Hydrated silica, SiO2·nH2O)

Diamond

Carbon (C)

Yellow Chert (Chert / Cryptocrystalline Quartz)

Silicon Dioxide (SiO2)

Chert (Flint Pebbles)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Specular Hematite (Iron Ore)

Iron(III) oxide (Fe2O3)

Rose Quartz with Feldspar Inclusions

Silicon Dioxide (SiO2)

Epidote with Feldspar/Quartz (Unakite-like)

Epidotized Granite (Ca2(Al,Fe)3(SiO4)3(OH) + KAlSi3O8)

Chert (Brown variety / Common Jasper)

Microcrystalline Quartz (SiO2)