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.