The following is a partial list of the colors of precious stones:

Shades of White.—Quartz, opal, chalcedony.

Shades of Gray.—Labrador, smoky topaz, chalcedony, zircon.

Black.—Obsidian, tourmaline, jet. Shades of Blue.—Lapis-lazuli, amethyst, chalcedony, spinel, zircon, sapphire, cyanite, tourmaline, turquois, odontolite, fluor spar.

Shades of Green.—Amazon stone, turquois, prase, beryl, blood-stone, epidote, emerald, malachite, chrysoprase, chrysolite, idocrase, olivine, garnet, chrysoberyl.

Shades of Yellow.—Opal, amber, topaz, beryl, jasper.

Shades of Red.—Garnet, carnelian, chalcedony, rose quartz, corundum, tourmaline, spinel, ruby.

Shades of Brown.—Zircon, garnet, smoky topaz, axinite, jasper.

Colorless.—Diamond, sapphire, spinel, zircon, topaz, rock crystal, moonstone.