Paraiba tourmaline. Neon electric colours, hard enough to use in all kinds of jewellery and extremel

Paraiba tourmaline.Neon electric colours, hard enough to use in all kinds of jewellery and extremely rare…What more could one want in a gemstone? In the early 1990’s, tourmalines with the most vivid colours yet seen appeared on the world’s gem markets. They came from pegmatites within one small hill in the Brazilian state of Paraiba and became very popular for their powerful saturated colours that seem to glow even in dim lighting. Copper often makes for stunning hues in minerals, and Paraiba tourmaline is no exception. The name is now officially used by gemmologists to describe any tourmaline coloured by copper impurities rather than its original geographical origin. In fact, an interaction between copper and manganese causes a variety of hues, from electric greens and blues to deep violets. The more valuable blue-green stones contain high levels of copper, and are sometimes heat treated to remove a pink component induced by manganese. Most normal tourmalines are coloured by iron.A group of gareimperos (artisanal miners) spent several years digging tunnels within the hill before these Kryptonite-like crystals first appeared in 1989. They were introduced at the Tucson gem show in 1990, and gained instant popularity with dealers and designers. As a consequence, the original source was mined out within five years. Prices quickly shot up to levels that were previously astronomical for a ‘semi-precious’ stone, five figures per carat are not uncommon for larger brighter stones. Even the initial price of $3000/ct was once seen as outrageous, but nowadays gem dealers would pounce on such a cheap deal.Further sources have now been found in Nigeria (2001) and Mozambique (2004). Five carats counts as a very large stone, and quality gems above two carats are extremely rare. The Nigerian ones have somewhat lighter (less saturated) colours, and come from an area that was next to Paraiba when South America and Africa were joined together, providing gemmological evidence of plate tectonics. Trace element geochemistry is used to distinguish stones from different sources, as the original Brazilian stones still carry a cachet in the market, even though the Mozambique stones are larger, often less included and equally colourful. The 10 x 8.2 x 4.5 cm crystal on matrix in the photo was mined from a pocket in Brazil.Isn’t nature’s palette wonderful?LozImage credit: Saphira Mineralshttp://bit.ly/2hJ3eJ8http://bit.ly/2ax7ppb -- source link

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