Tanzanite
Tanzanite is a rare gemstone, a type of mineral zoisite. Only one of its deposits is known in the world – in the north of Tanzania, which was discovered in the middle of the 20th century. The name in honor of the producing country was given to this stone by the president of Tiffany & Co. Henry Platt. The classic color is blue-violet. This color is almost always the result of heat treatment of the stone. Most unheated samples have a brownish color. The most expensive samples are vivid blue. There are also specimens of blue and greenish-blue with a purple hue.