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Why Tanzanite?

Tanzanite is a supremely rare gemstone, coming from only one source in the world, the Merelani Hills of Tanzania (Tanzania Resources), in the shadow of Mount Kilimanjaro. This makes tanzanite about one thousand times rarer than diamond. Tanzanite varies from a deep "sapphire" blue to an "amethyst" purple. Once polished, tanzanite radiates different colours from each of its three crystallographic axes, resulting in a mesmerising violet-blue.

History of Tanzanite

There are many conflicting reports about tanzanite's discoverer. The earliest entry reports that tanzanite was found in 1962 by a Polish immigrant who lived in Arusha, a town in the foothills of Mount Kilimanjaro. A member of the British Gemmological Survey supposedly identified the material, but nothing came of this. Some suggest that Tanzanite was discovered by Manuel D'Souza in 1967 (but tribal stories insist that Ali Juuyawatu, a Masai tribesman, was the stone's founder). D’Sousa, originally from India (or Portugal depending the story), had been looking for stones in the wilds of Tanzania when "some natives" took him to an area about 97 kilometres southwest of Arusha. He soon realised the blue stones he had found were not sapphires, but staked a claim and began mining anyway. Henry Platt of Tiffany and Co. named the new gem "Tanzanite" and Tiffany's began a marketing campaign to introduce it to the public.

Following its release to the world in 1969, the demand for tanzanite steadily increased. In the early 1990's, prices took a drastic leap up by 40% for the fine quality stones. By 1993, the Tanzanian government developed regulations and sanctions to ensure the longevity of the stone. In general tanzanite will probably be around for many more years, but the finer quality tanzanite will not. Approximately 10% of the material coming out of the mine today would qualify as high-grade tanzanite. The Smithsonian Institute has two notable examples; one faceted stone weighing 122.7 carats, and a rare cat's eye tanzanite weighing 18.2 carats.

Kilimanjaro facts

Is the highest mountain in Africa, located in Northeast Tanzania, near the Kenya border about 330 kilometres south of the Equator. It is made up of three extinct volcanoes: Kibo 5,895 meters (19,340 feet), Mawenzi 5,149 meters (16,896 feet); and Shira 3,962 meters (13,000 feet). German missionary Johannes Rebmann was reported to be the first person from the western world to report the mountain. He submitted his findings to the Royal Geographical Society in 1848. On 6 October 1889 Dr. Hans Meyer, with Ludwig Purtscheller finally climbed the summit. Kilimanjaro  is also known as Kilima Dscharom, Kilimandscharo, Kilima Njaro (Swahili) and Oldoinyo Oibor (Masai).

    03o07' South
    37o21' East
    5,895 meter
    19,335 feet
 Volcanic status

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Physical properties

Tanzanite is pleochroic, that is, it shows different colours when viewed in different directions. One direction is blue, another purple, and another bronze, adding subtle depths to the colour. When tanzanite is found in the ground its bronze colour dominates. However, with gentle heating the blue colour forms and then deepens 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 started 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 colour and picked the crystals up, unwittingly becoming the first tanzanite collectors. 

Tanzanite is in the orthorhombic crystal system. The crystal class is 2/m2/m2/m, while its space group is Pnmc. It has common forms of {100}, {111}, and {001}. Tanzanite is a hydrated calcium aluminium silicate mineral with a chemical formula of Ca2Al3Si3O12(OH). It is 18.76% calcium, 12.63% aluminium, 19.71% silicon, 24% hydrogen, and 48.67% oxygen.

  Molecular weight 427.38 gm
  Refractive index 1.69 to 1.70
  Hardness 6.0 to 6.5 (Moh's scale)
  Specific gravity 3.35
  Density 3.26 to 3.38

Metaphysical properties

Tanzanite reputed to help deal with change and to uplift the spirit and open the heart. The blue and purple hues of the stone are associated with generosity and friendship. Tanzanite allegedly helps against insolence and wantonness and prevents thoughtless deeds, and harmonizes sexual lust and erotic feelings of a partner.

The American Gem Trade Association added tanzanite to turquoise and zircon as a third December birthstone, and it is also listed as an alternative gem for the star sign Capricorn.

Synthetic Tanzanite

Despite claims tanzanite has not yet been synthetically created in the laboratory, there are really good tanzanite fakes being sold on the market. Some are genuinely advertised as artificial while others are intended to deceive buyers. Tanzanite sold as “laboratory created” is either spinel (Magnesium Aluminium Oxide, MgAl2O4), or synthetic sapphires that mimic tanzanite. Since 1991, rumours have circulated that Russian scientists are manufacturing synthetic tanzanite, although there is no supporting documentation or commercially available examples.