Tanzanite is one of the most rare and beautiful stones in the world. It was discovered in 1967 in Tanzania, at the foot of Mount Kilimanjaro (Mererani plateau, province Arusha). Tanzanite deposit was allegedly found by the locals, the shepherds of African Masai tribe, in place of burnt clearing. They brought the stone weighing about 2 kg to Manuel de Souza (also called “mad Manuel”), who was in Tanzania with an expedition to search for rubies at that time. Large transparent crystals of violet and burgundy shades were first taken for sapphires, but these stones were softer. Soon it was discovered that this mineral was a variety of zoisite, and the characteristic bluish color was due to impurities of chromium and vanadium. At the official presentation in 1986, tanzanite was announced the most beautiful of all blue gemstones found in the last 2000 years.
Weight of the largest tanzanite found at the foot of Mount Kilimanjaro, was more than 3 kg (16, 839 carat) It was named “Mavanzi” after the highest point of the mountain. It is known that the value of the stone is still not appraised.
From the history of tanzanite
Since 2004 tanzanite mining is carried out by «Tanzanite One Group». The stone is quarried by underground method in the mines of about 400 meters deep. New significant deposits of the stone are still not found, so every year tanzanite confirms its title of one of the rarest stones in the world. As a result, its cost also increases (the price per carat today is thousands of dollars, and it largely depends on the color of the stones).
It should be noted that an important role in the history of tanzanite belongs to the jewelry house “Tiffany & Co.”. The unique beauty of the stone was highly valued by the President of “Tiffany & Co.”, Henry Platt. It is believed that he did not like the name of the mineral zoisite, as it sounded like “suicide”, that’s why he offered the name “tanzanite” associated with the deposit of the stone. Soon tanzanite appeared in many collections of “Tiffany & Co.”, which attracted much attention of designers and celebrities. It is known that tanzanite sparkled in the film “Titanic” by James Cameron, jewelry with this stone also wore Elizabeth Taylor.
The use of tanzanite
Tanzanite is very precious jewelry stone. Since it is extremely fragile, one should work with it very carefully not to damage it during cutting. This stone does not react well to sudden changes in temperature; it can not be cleaned with acids or ultrasonic baths. The owners of products with this stone should be also very careful: such jewelry is worn extremely rare, for the most important events. Nevertheless, tanzanite jewelry is always a sign of high style, elitism and genuine luxury.
Coloring of tanzanite
Rich, deep, intense color is typical for larger stones of tanzanite, while smaller ones are characterized by lavender color. This stone may also have a “alexandrite effect» («color shift effect»): at different angles one can see tri color of bright blue, lilac-purple hues, “brown-yellow savannah” with bright green and golden sun shades.
The stones that are closer to the surface, are characterized by blue-violet color. Initially tanzanite crystals are brown or greenish, and then they are subjected to a special heat treatment: at the temperature of + 375C – for about one hour, and when heated up to +600C – only for a few minutes, otherwise a complete discoloration of crystals occurs. Thus, tanzanite shows a beautiful rich color of blue and violet shades with purple shimmering.
The most expensive are considered to be “royal tanzanites”. In daylight such rocks show up to 80% of the primary deep blue color with a purple shimmering. Under artificial light these rocks show reddish-purple hues. When cutting, the masters do their best to strengthen exactly blue color in tanzanite.