Precious stones: various gems used in jewellery.
White diamond: pure and crystallized carbon.
Green emerald: green and translucent beryl.
Red ruby: corundum made up of aluminum oxide containing chromium.
Blue sapphire: corundum made up of aluminum oxide containing titanium.
White-blue aquamarine: green-sea or blue-sea beryl.
Yellow topaz: pale yellow orthorhombic crystal.
Purple amethyst: macrocrystalline quartz.
Garnet-red: very hard precious stone.
Green tourmaline: semiprecious stones of different colors.
Turquoise: blue-green triclinic crystals.
Pearly white opal: quartz containing from 6% to 10% water.
Blue lapis lazuli: decorative stone.