Tanzanite – An African Treasure

Tanzanite Diamond Ring

Many of the most desirable gemstones in existence have been known about for hundreds, if not thousands of years, but there are still new treasures hidden beneath the earth waiting to be found. Geologists searching for new deposits of known materials occasionally make incredible discoveries which end up having far reaching consequences.

In 1967 a part-time gold prospector living in the city of Arusha in the east African nation of Tanzania found shards of a transparent blue mineral on a ridge some 40km from the city. Initially assumed to be the bright green stone Peridot, these fragments were analysed by professional gemmologists in the country, but they only succeeded in proving that the stone was not the valuable aquamarine, or the non-gem mineral dumortierite. It was only when samples reached the Gemological Institute of America that it was identified as blue zoisite, the only samples encountered up until this point.

It was the high-end retailer Tiffany & Co who realised that the stone’s characteristics made it an extremely desirable stone for use in jewellery. Unfortunately “Blue Zoisite” sounds a great deal like “Blue Suicide”, and the company rightly decided that a more marketable name was necessary to present this new gemstone to the public. They settled on Tanzanite, naming the stone after the only nation where it would ever be found, and boldly stating that the stone could be found only in two places; “Tanzania or Tiffany’s”

Characteristics

Where other blue stones such as sapphires exhibit a single colour throughout, Tanzanite exhibits a phenomenon known as trichroism where different colours can be revealed under different lights or at different angles. Though most stones are primarily blue, and can be as vivid a hue as that of a blue sapphire, the stones exhibit flares of violet and even burgundy, with the quality and vibrance of the colours determined by the light which falls upon the stone.

Other precious stones, such as opals and alexandrite, exhibit similar plays of different colour through their surfaces, but with Tanzanite the true extent of its variety of hues was only revealed through heat treatment which removed the reddish brown tint from the raw stone.

When properly processed and faceted the tanzanite is an extraordinarily exciting gemstone. When set into earrings or rings with an accompaniment of diamonds the stones play to one another strengths, magnifying both the scintillation of the diamond and the trichromism of the tanzanite to create something truly unique.

Rarity

Tanzanite has only ever been found in a single stretch of deposits near the Mererani Hills, and this deposit has been extensively mined in the decades since its discovery. Gemmological surveys indicate that the mines still have more to give, but the lack of any new sources mean that Tanzanite is very much a finite resource.

In the 1970s the Tanzanian government nationalised the mines, citing its superior resources as a means of protecting and building up the country’s mining operations. Unfortunately the government’s lack of knowledge and skilled labour, along with failed measures to consolidate processing and prevent smuggling, meant that three decades passed with very little mining taking place.

Nowadays the government holds only partial control over the mines, shared with private sector mining operations which have worked hard to combat illegal trade in these beautiful stones and ensure that the people of Tanzania profit from the fruits of their labour.

At Laurelle Antique Jewellery we have some of the finest selection of tanzanite rings, earrings, pendant and brooches each fashioned lovingly by master craftsmen to showcase this rare and beautiful stone.