Scientifically, tourmaline is not a single mineral, but a group of complex crystal silicate mineral compounded with elements such as aluminum, iron, magnesium, sodium, lithium, or potassium. Tourmaline can be found in a wide variety of colors from colorless to black. This, makes tourmaline one of the most popular gems among collectors. Iron-rich tourmalines vary from black to deep brown, magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are almost any color: blue, green, red, yellow, and pink.

Tourmaline has been used in jewellery since 1703 when the Dutch began to important them from Sri Lanka. The name is derived from the Sri Lankan word tura mali, meaning the stone of mixed colors.

Tourmaline occurs as an accessory mineral in acid rocks, such as granite, particularly in pegmatites, and also in metamorphic rocks, such as schists and crystalline limestones; it has often resulted from the action upon the rocks of hot acid vapours emitted from below the earth's crust.

Tourmalines are usually heat-treated to enhance the color of the gemstone. Heat removes the pink or red component from tourmalines, producing colorless stones from pinks and reds, blues from some browns and purples. Very pale pink, green or blue tourmalines frequently become a deeper pink to a red on irradiation.

Hardness on Moh's Scale : 7-7.5

Refractive Index : 1.614 - 1.666

Specific Index : 2.82-3.90

Crystal System : Trigonal

Birthstone : October

Approx carat weight :

4x4mm - 0.20 ct

5x5mm - 0.36 ct

6x6mm - 0.62 ct