Tanzanite-What a spectacular color!
 

Tanzanite is a very special and unique gemstone.  Its name reminds of the world-wide unique occurrence in the east-African state of Tanzania. Africa – the name of this continent does not immediately remind us of gemstones. Nevertheless, Africa is a continent from where many splendid and beautiful stones find their way to the world markets. An example for this is Tanzanite, which was enthusiastically celebrated after its discovery in 1967 as "Gemstone of the 20th Century” The gemstone experts literally held their breaths when they were shown the first deep blue crystals mined in the Merelani Hills near Arusha in the north of Tanzania. Millions of years ago, metamorphous slates, gneiss stone and quarzites shaped impressive flat insular mountains on the wide planes near Mount Kilimanjaro. In the core of these unusual rises there are stored the valuable crystals. For a long time they remained hidden for the eyes of men, until one day some Massai-herdsmen passing by noticed crystals sparkling in the sun and picked them up.

The Tanzanite trade is managed by many, usually small-scale licensed traders who have built up good business relationships with gemstone firms in Germany, India, Israel and the USA. An estimated 90 per cent of all Tanzanite traders are registered members of the International Colored Stone Association ICA and thus dedicated to the respective high ethical standards of ICA. In this way, then this exclusive gemstone is not brought to the world markets via suspicious back-street dealers, but in spite of its rarity is distributed via reliable and trustworthy official channels to well-reputed gemstone-cutters, and then passed on to the most important jewelers all over the world.

Spectacular and magnificent is the deep blue of Tanzanite, ranging from ultramarine to a light purplish blue. The most coveted colour is a blue which shows a purplish hue shimmering around it, which is extremely spectacular in sizes above ten carats. Typical for Tanzanite is the appearance of several colours in one and the same stone: depending on the perspective, the stone appears blue, purple, or dun yellow. Most rough crystals, however, show a disturbingly large proportion of brownish-yellow, but the cutter may cure this by carefully heating the stone in an oven to about 500°C. In the course of this heating , utmost concentration is demanded, for it is essential to determine the moment when the colour turns blue. Heating is therefore a treatment which is generally accepted in the trade, however, the rough stone has to be as free of inclusions as possible, as otherwise the process will lead to fissures in the stone.  Tanzanite's have a hardness of  6.5 on Moh's Hardness Scale.