Tanzanite is said to have formed over 585 million of years ago when the formation of the rift valley and the resulting geological events caused the crystals to grow in deposits on a plain found in the shadow of Mount Kilimanjaro.
This beautiful gem remained undiscovered though until only just over forty years ago. There are many versions of the story of the discovery of Tanzanite in 1967, but most believe that it was one day, when some passing Maasai shepherds were passing through, they noticed the sparkling crystals lying in the sun and picked them up to take with them.
It was the Maasai tribesman Ali Juyawatu who first shared his blue-violet crystal fi and with Manuel de Souza, who was a tailor by profession and prospector by passion, and he was the one to bring the gemstone into the limelight, initially thinking that these were particularly brilliance sapphires.
It was realized instead that this is a completely new gemstone and it was found to be the mineral “zoisite”, and it was labeled ‘Tanzanite’ after its place of origin by the famous jewelers Tiffany & Co. In 1969, when the Tanzanite hit the American market, it was immediately celebrated, calling it the ‘gemstone of the 20th century.
Today Tanzanite is recognized and loved all over the world and is an especially beautiful memento of Tanzania.
The only known source of this incredible gemstone is a five square mile hilltop at Merelani, in the foothills of Mount Kilimanjaro.
Tanzanite, or Zoisite, is naturally found in a variety of colors ranging from blue to violet with flashes of red and different shades of green, yellow, brown and even pink. The blue variety of the gemstone is then called Tanzanite. It easy to identify and difficult to duplicate as it is a trichroic gem, which means that it has three layers of color.
The multi-colored stone is then usually heated carefully at 500 degrees Celsius to give it the lustrous purple-blue that it is famous for. The heating process does not enhance the color like other gemstones, it just removes the colored(especially brown) axis leaving the blue/violet axis intact.
So a medium grade Tanzanite before heating will turn pale blue/violet after heating, but still remain medium grade. A top grade one be deeply saturated with color even before heating and turn the very deep blue/violet after heating.
Tanzanite has a refractive index of 1.69 and, with a value of 6.5-7 on the Mohs scale, it is not a particularly hard gemstone. It is similar in hardness to Emerald, but not as brittle. For this reason, it advised to be worn with some care.
Like other gemstones you have to follow the 4 degree Celsius with Tanzanite as well.
The best and most valuable Tanzanite are considered those with the deepest shades of purple and blue. The color grading of Tanzanite starts at the top with ‘AAA’ which are the stones of deepest color, and these are found in the larger and rarer gems.
The larger the gum the more intense the concentration of color and the darker the gemstone. Then the color becomes slightly lighter in the next grade down which is ‘AA’, and then to the paler, but still beautiful shades of ‘A’, ‘B’ and ‘C’. The choice of color is very subjective and ultimately depends on what each patron finds pleasing.
The clarity of Tanzanite is defined by the process of inclusions. The best stones are ones that contain no inclusions that are visible to the naked eye and are considered eye clean. In these, the best gems are graded as ‘IF’ which means that the gem is internally flawless, and after that there are the gems which are graded as ‘VVS’.
These have very very small natural inclusions(what are known as bubbles and needles, but not any cracks) which are not visible to the naked eye and these stones are also eye clean. The grades after that are for gems with heavier inclusions and fissures. All our gemstones are carefully examined and graded by experts, so you can be confident in the quality of the gem that you purchase.
Tanzanite off sizes are cut into both traditional and fancy shapes and the quality of the cut of each gem depends on the proportion of the stone and the angle of its facets, which are positioned to reflect light appropriately. It is very precise process in which each facet of the Tanzanite is carefully cut and polished by our qualified and experienced gem cutters to give the finished gemstone maximum sparkle and brilliance.
When a gem is being cut in the lapidary, the gem cutter will try to ascertain which shape to best cut the stones into the seeing what shape will give the least amount of wastage.
There are certain shapes which are more abundant for this reason, such as oval, pear, trillion and cushion. The shapes such as round, square, emerald and heart are slightly more expensive to cut because in these a lot of the raw stones has to be shaved off to give the desired result.
The weight of cut Tanzanite is measured in carats and one carat is equal to one fifth of a gram. The size a stone appears to be depends on both the carat weight and the proportions of its cut.