Tourmaline ranks 7 to 7.5 on the Mohs hardness scale.   Hardness and toughnessGem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder...

Tourmalines are gems with an incomparable variety of colours. The reason, according to an old Egyptian legend, is that the tourmaline, on its long journey up from the centre of the Earth, passed over a rainbow. In doing so, it assumed all the colours of the rainbow. And that is why it is still referred to as the 'gemstone of the rainbow' today.The name tourmaline comes from the Singhalese words...