Tanzanite: Prize of a Gem safari
The gemstone discoveries in East Africa in the 1960s transformed the jewelry world: new varieties, new colors, and new variations on existing species made that decade the most exciting time in the gemstone industry in our lifetimes.
But no gemstone discovered in East Africa has had more of an impact on the world gemstone market than tanzanite, a velvety blue variety of the mineral zoisite that was found for the first time in 1967 and named after the country of its birth by Tiffany & Co in New York, who introduced the gemstone to the world market in 1969.
Tanzanite is the ultimate prize of a gem safari. Its rich purples and blues often have a depth comparable to the finest sapphire. Paler tanzanite has a delicate periwinkle color like the eyes of Elizabeth Taylor. It is supremely rare, coming from only one place in the world, the Merelani Hills of Tanzania, in the shadow of Mount Kilimanjaro.
Recently, new mining techniques and the liberalization of the Tanzanian economy has helped to boost production in the past few years to make tanzanite more available than ever before in the history of the gemstone. And its rich dramatic color is now surprisingly affordable.
The source of its mesmerizing color is that tanzanite is trichroic: that is, it shows different colors when viewed in different directions. One direction is blue, another purple, and another bronze, adding subtle depths to the color. When tanzanite is found in the ground, the bronze color dominates. However, with gentle heating, the cutter can watch the blue color bloom and deepen in the stone.
Legend has it that the affect of heat was first discovered when some brown zoisite crystals laying on the ground with other rocks were caught in a fire set by lightning that swept through the grass covered Merelani hills northeast of Arusha. The Masai herders who drive cattle in the area noticed the beautiful blue color and picked the crystals up, becoming the first tanzanite collectors.
Choosing a Tanzanite
Tanzanite jewelry is a little more delicate than other gemstone jewelry and should not be set in a ring that will be worn during strenuous activity. Never clean tanzanite in an ultrasonic cleaner or resize or repair a ring set with tanzanite because the stone could shatter in the heat of a torch. It is available in a variety of shapes and sometimes in large sizes that are perfect for an important necklace.