Gemstone

Turquoise

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

Amethyst

Amethyst (Silicon Dioxide - SiO2 with ferric iron impurities)

Pyrite

Iron Disulfide (FeS2)

Fluorite

Calcium Fluoride (CaF2)

Raw Diamond (Rough Uncut)

Diamond (C - pure carbon)

Aquamarine

Beryllium aluminum silicate (Be3Al2Si6O18)

Labradorite

Labradorite (Plagioclase Feldspar Series) - (Ca, Na)(Al, Si)4O8

Citrine

Citrine (Silicon Dioxide, SiO2)

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Sodalite

Na8(Al6Si6O24)Cl2 (Sodalite)

Chert (often called Flint or Jasper based on color)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Prehnite

Prehnite - Ca2Al(AlSi3O10)(OH)2

Amethyst

Amethyst (variety of Quartz, SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Smoky Quartz (Tumbled)

Silicon Dioxide (SiO2)

Pink Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Milky Quartz

Silicon Dioxide (SiO2)

Chert (White Chert/Flint)

Chert (Microcrystalline or Cryptocrystalline Quartz, SiO2)

Blue Topaz

Al2SiO4(F,OH)2 (Fluorine-bearing aluminum silicate)

Goldstone (Red/Brown)

Aventurine Glass (SiO2 with Copper inclusions)

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (Jasper/Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Amazonite

K(AlSi3O8) - Lead-bearing Microcline (Tectosilicate)

Rough Quartz (with potential Host Rock)

Silicon Dioxide (SiO2)

Ferro-Manganese Slag

Vitreous Silicate Slag

Breccia

Clastic Breccia (General mineral composition depends on fragments, often SiO2 or CaCO3)

Green Chert

Microcrystalline Quartz (SiO2)

Charoite

Charoite (Hydrated silicate of potassium, sodium, calcium, barium and strontium): (K,Sr,Ba)(Na,Ca)2[Si4O10](OH,f)·H2O

Chert (Jasper/Chalcedony)

Microcrystalline Quartz (SiO2)

Aquamarine

Beryl (Be3Al2Si6O18 with iron impurities)

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

Blue Sapphire

Corundum (Al2O3 with trace Titanium and Iron)

Jade

Jadeite or Nephrite (both are commonly referred to as 'jade'). Jadeite: NaAlSi2O6; Nephrite: Ca2(Mg,Fe)5Si8O22(OH)2.

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Quartz / Quartzite

Silicon Dioxide (SiO2)

Diamond (Green tinted)

Carbon (C) with trace impurities or lattice defects

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Basalt with Olivine Phenocrysts

Porphyritic Basalt (containing Mg2SiO4 - Fe2SiO4)