The tourmaline is a real miracle of color. It not only comes in green, red, blue, yellow, colourless and black, but also as a multi-coloured or colour-changing gemstone or as a cat's eye. Most of the yellow tourmalines found thus far had a slight tinge of brown. Meanwhile, this colourful gemstone has taken the world by surprise again with another new variety, and this time it is a yellow one: in southern East Africa, in Malawi, a gemstone deposit with some wonderful yellow tourmalines was discovered in the autumn of 2000. The fresh, springlike yellow of these tourmalines is clear and pure and has just a very fine hint of green. Under the trade name 'canary', the new tourmaline variety has now begun to circulate. It is fine traces of magnesium that are responsible for the electrifying yellow colour. The treatment only brings about the desired result because tourmalines typically display different colours and different colour intensities in different directions. By heat treatment, the tourmaline's second colour, in this case a light brown, is also transformed into the coveted radiant yellow. Large yellow tourmalines are rare in Malawi too, the more so in view of the fact that only some 10 per cent of the yield is actually of gemstone quality at all. Experienced cutters are particularly fond of working on these gemstones, and say that these are the only gemstones that smell good. One day, the owner of the gemstone mine in Malawi discovered that the unwanted black material was easier to remove if the raw crystals were first boiled in water to which lemon juice had been added. So since then, the yellow tourmaline crystals from Malawi have had not only the pleasant colour of fresh lemons, but also their fragrance.
ليست هناك تعليقات:
إرسال تعليق