Tanzanite is a member of the mineral family zoisite, which has been known for nearly two hundred years. Zoisite occurs in a number of varieties, the most sought after being Tanzanite. This mineral family was named zoisite in 1805, some time after the Austrian scientist Baron Siegmund Zois von Edelstein (1747-1819) had identified the mineral in the Saualpe Mountains of Carintha, Austria. Siegmund Zois von Edelstein operated an iron mine in the Karawanken Mountains in Karnten, Austria, and encountered the mineral on his own property. Centuries later, the discovery of a bright-blue transparent variety that we now know as Tanzanite, created much excitement in the specialist world.

A prospector named Manuel d'Souza, who was searching for Sapphire, discovered Tanzanite, in 1967, in northeastern Tanzania. D'Souza was originally from India. He had been looking for stones in the wilds of Tanzania. Eventually, some natives guided him to an area in the region of the Merelani Hills near Mount Kilimanjaro, around 90 kilometers from his home town of Arusha.

There, he found these precious Blue stones he thought were Sapphire. According to legend, the Masai herders were actually the ones who originally discovered the stone, when a lightning strike set the surrounding grasslands on fire. When they returned to the land with their livestock, the blue stones were all over the ground. D'Souza soon discovered that the Blue stones he had found were not Sapphire, so he staked a claim with the government and began mining.

Mined, uncut Tanzanite.

With few inclusions, by 1970, the Royal Blue find was soon the focus of American and European publicity. When word of the new gemstones was revealed, there began a marketing campaign to introduce it to the public. Now, Tanzanite is the pride of the gem-rich East African country, Tanzania.

Some say D'Souza's discovery is one of the most exciting in the field of gemstones in nearly a century. Of all the new gemstones that have conquered the hearts of people in the second half of the twentieth century, none has even approximated the success of Tanzanite.

Within a relatively short period of time, Tanzanite has succeeded in achieving worldwide popularity and major acclaim. The triggering factors for this market success are the virtues incorporated in tanzanite such as the beauty of its color, its rarity and durability, as well as its availability. Though it only rates a 6.5 on the hardness scale, Tanzanite's resistance to scratching and abrasion is relatively good.

Tanzanite has become one of the most popular gems in the marketplace. In fact, it is now the most popular gemstone after the "Big Four", which consists of Diamonds, Rubies, Sapphires, and Emeralds. At first, the gemstone was only available in smaller sizes, but now much larger sizes are cut and sold. Today, Tanzanite is far less expensive than Sapphire, for which it often serves as a substitute.

Tanzanite stones are 585 million years old. There are apparently only very rare Tanzanite stones that are naturally blue. Given its attractive color, rarity and the publicity, which greeted its discovery, the value of Tanzanite makes it one of the most valuable, somewhat less than that of the violet-blue Sapphires Tanzanite resembles.

Tanzanite is, however, rarely seen on the market--and therefore is very much a collector's item.

The Smithsonian Institution exhibits an impressive collection consisting of a one-faceted stone of 122.7 carats and a rare Cat's Eye Tanzanite of 18.2 carats.

Physical Properties and Science of Tanzanite

Tanzanite rates a 6.5 on the hardness scale and has a vitreous luster. It is a relatively soft and brittle stone, nowhere near as hard as Sapphire, or Diamond, but given roper care, it can last a long time.

The typical color of Tanzanite is blue with a violet tinge. In some lighter-colored stones, the color is described as lavender. The color of the tanzanite is the most important factor in determining its price. For example, a Tanzanite of the perfect blue brilliant hue in 5, 10 or 20 carats is of greater value than a paler, darker, or duller stone of twice the size and weight.

In nature, Tanzanite only sometimes occurs as a blue stone, but more often is golden to brown in color. After some time, it was discovered that by heating the brown or golden variety of the stone to 600 degrees Celsius and gradually cooling it, the color could be permanently changed to the violet-blue color. Without heating, tanzanite would be unmarketable.

Tanzanite is pleochroic, meaning the purple, gray, blue and violet tones within the stone vary depending on the angle the stone is viewed from. There might also be a slight color change in incandescent light, when stones may appear to be more violet. Tanzanite's color is caused by the amount of chromium present in the stone.

Tanzanite's rich, royal velvety blue resembles the precious Kashmir Sapphire. With only a hint of violet and a slightly less hard and lustrous appearance than Sapphire, this serves to inform experts that the stone is Tanzanite rather than Sapphire. While at one point in time, Tanzanite was substituted as a less-expensive alternative to Sapphire, it is now appreciated far more for itself and far less as a Sapphire substitute. Tanzanite is much softer and fragile than Sapphire and can occasionally shatter. It is important, therefore, if you are having your Tanzanite repaired or cleaned, that you make it clear that it is a Tanzanite stone, so extra care may be taken.

Tanzanite is often round or oval cut. It is a stone that normally has few inclusions, but as in all gemstone families, large, clear, nearly flawless Tanzanites are rare. The larger the stone, the greater the chance of flaws occurring. Being little known and of very recent history, this stone has neither been imitated, nor has Tanzanite been produced synthetically. Tanzanite's fire factor, especially that of the splendid blue color, is comparatively high, for this reason the Tanzanite alone of all the Zoisite family can be classed with any other splendid gem. Tanzanite is a rare gem likely to appreciate in value as a collector's item.

Tanzanite Jewelry

Tanzanite occurs in schists and gneisses as well as in metasomatic rocks together with Garnet. It is also occasionally found in hydrothermal veins. Tanzanite is found in very limited quantities, almost exclusively in the northern part of Tanzania, near the Merelani hills, where the chief deposit is almost exhausted. However, small amounts of Tanzanite has also been found in Sweden, New Hampshire, U.S.A., Pakistan, South Africa, Kenya, Norway, Austria, and Italy.