The colour range of this gemstone, from sea green to turquoise blue, evokes dreams of summer, holidays, remote Caribbean beaches and pure relaxation. But it can do a lot more than that.
The gemstone, originally only found in a few mines in the federal Brazilian state of Paraíba, is not only rare and precious, but also incomparably colourful and vivacious. It is the most valuable variety among the tourmalines, a group of gemstones consisting of mixed crystals, in which, for a long time, practically all the colours of the rainbow were represented except for a pure, radiant turquoise blue. Until the end of the 1980s, that is, when the gemstone pioneer Heitor Dimas Barbosa finally fulfilled his dream of discovering a ‘really special gemstone’ in the federal state of Paraíba: in a tunnel of the ‘Paraíba hill’, later to become a legend in its own right, the first tourmaline crystals came to light in hues of a unique intensity, from emerald green to turquoise blue.
It is the element copper that produces these hues with their neon shine. The paraiba tourmaline also contains manganese, and it is the interplay of these two elements that creates its colour range. Copper, in a high concentration, evokes the coveted blue, turquoise and green tones, whilst manganese brings out fine hues from red to violet. The gemstone industry takes advantage of this ‘division of labour’ between the elements: with the standard commercial heat treatment process, the reddish colour component in the raw stones can be eliminated, so that only the pure copper colour appears. Having said that, some of the red to violet nuances are so wonderful that they do in fact come on offer as special rarities – to the delight of true connoisseurs.
It is not until after a paraiba tourmaline has been cut that the extraordinary vivacity in its colour is revealed. If faceted perfectly, this gemstone seems positively to bubble over with brightness. In no time at all, it became one of the world’s most valuable gemstones. Sadly, hardly any large raw crystals have ever been found, either in the first deposit – completely exhausted meanwhile – or in the nearby gemstone mines worked later on. That is the reason why relatively large specimens have such a high profile in the trade.
Meanwhile, however, the paraiba story has found an unexpected sequel in Africa. For several years now, cupreous tourmalines in the typical ‘paraiba colours’ with their intense radiance have also been coming from Nigeria and Mozambique. They too get their beautiful colours from the interplay of copper and manganese; their chemical composition is identical to that of the Paraíba stones. For this reason, no distinction is any longer made in the trade as to whether a paraiba tourmaline comes from one of the mines in Paraíba or from Nigeria or Mozambique.
This valuable gemstone, by the way, is also of interest as a witness of the continental drift. At the time when, some 300 million years ago, the gemstones were formed in the interior of our Earth, what is now South America was still nestling in close to the African continent, almost like a piece in a jigsaw puzzle. Slowly, the continents drifted further and further apart – and with them, the birthplaces of these wonderful gemstones.