Tourmaline or it’s rather unattractive name of ‘Borosilicate of Aluminium’ is quite the rainbow stone…
The gemstone was brought from Ceylon to Europe in the 18th Century by the Dutch. They gave these gems the Sinhalese name of ‘Turamali’ which is thought to mean stone with mixed colours.
Tourmaline is found in a vast array of colours such as pink, chrome green, neon blue, yellow and the very rare red. The names for these are:
Indicolite – blue tourmaline
Rubellite – Dark pink to pinky-red tourmaline
Schorl – Black tourmaline
Achroite – Transparent
Dravite – Brown Tourmaline
Siberite – Reddish-violet Tourmaline from Siberia
Chrome tourmaline – attractive dark green
Paraiba Tourmaline – Neon blue
Tourmalines can show interesting colour effects. At times these colours appear in layers, giving what is known as a “watermelon” effect.
Tourmaline also exhibits strong dichroism , sometimes chatoyancy (cat’s eye) and can have extensive fibrous inclusions – what a complicated gemstone it is!
The most valuable Tourmaline is natural neon blue, ideally from the Paraiba mine in Brazil, which are very expensive and rare. Genuine examples of these are now extremely rare & thus expensive, if you are lucky enough to be in the market for one of these beauties you’ll need a reputable gem-lab certificate to accompany the stone as there are many treatments available.
Tourmaline has a hardness of 7-7.5 on Moh’s scale making it suitable for most jewellery but probably not engagement rings.
Tourmaline localities: Brazil, Madagascar, Russia, USA, Sri Lanka, Africa
Tourmaline is a big favourite of mine, there is a colour to suit everyone with many affordable varieties – the Paraiba will be remaining on my wish list for the foreseeable future 🙂