Tourmaline
Tourmaline is the name given to a group of 14 minerals of which elbaite and schorl are the most common. Tourmaline can be found in South Africa, Namibia, Zimbabwe Mozambique and Swaziland. Tourmaline is found in a wide spectrum of colours ranging from black, green, blue, orange, pink, yellow, red and watermelon
Chemical Formular : A(D3)G6(T6O18)(BO3)3X3Z
Refractive Index : 1,616 – 1,65
Hardness : 7 on the Mohs Scale
Crystal System : Trigonal