Hardness 7-7.5, Specific gravity 3.1-3.25, Refractive index 1.61-1. 67

Tourmaline is found in a variety of colors. The variety is due to the chemical composition. Most tourmalines are composed of silicate and borate of aluminum or magnesia and iron. Tourmaline does not have a cleavage and is a durable gemstone.

Depending on the color, tourmalines are known by different names. Red and pink tourmalines are called rubellite; blue, Brazilian sapphires; colorless, achorite; yellow to yellow green, Ceylonese peridot; green, Brazilian emerald; and violet to red purple, siberite.

Brazil is the main source of tourmaline, but yellow and brown stones are found in Sri Lanka, reds and pinks in California, reds in Myanmar (Burma), reds and greens in Brazil and Russia, and reds, blues, and greens in the USA.

The colors of the stones can be changed by heating or irradiation, but the change is not always permanent. Tourmaline is often cut into a rectangular shape that follows its naturally long and narrow crystal formation. Green tourmaline is often mistaken for emerald, and the blue variety is mistaken for blue sapphire.

Wearing tourmaline increases the wearer's intelligence, and improves concentration. Tourmaline can help someone financially and can be used as a general good-luck stone. Politicians and leaders can wear tourmaline to good effect. It should be set in silver.Different colors of tourmaline are used to substitute for diamonds, rubies, emeralds, blue sapphires, and yellow sapphires.