The Merelani Hills within the Lelatema Mountains, Simanjiro District, Manyara Region of Tanzania are a prized locality amongst the mineral world, almost purely for the world's only occruance of a gemstone that is 1000× rarer than Diamond. The gemstone in question is none other than the very rare Zoisite variety that is aptly named Tanzanite.
This exceptional singular Tanzanite crystal boasts an incredible degree of optical transparency, with lustrous faces and a perfect termination to match. The species is famed for it's midnight blue-violet colouration as much as it is famed for is dichroic nature. The colours on display on this crystal shift, as if by magic, from blues and greens to purple, orange yellow and red depending on the viewing angle and also which axis of the crystal is being viewed. This natural, dichroic effect is magnified tenfold when viewed against a polarised screen backdrop (computer screen) as seen in the accompanying video we have provided. Look closely and you will see the crystal has a beautiful green internal phantom towards its core that has a striking blue phantom sitting just above it.
As a highly sought-after gemstone material, Tanzanite is almost always heat-treated to achieve the desired colouration but this heating process causes the crystal to lose its dichroic properties. This crystal has luckily avoided such a fate, and instead of being cut and processed for gemstone use, has instead been prized for its mineralogical potential as a specimen worthy of high-end collections.
Internally, the crystal features a prominent area toward the termination that is devoid of fractures whilst featuring fractures towards its base. These 'fractures' are a common feature of Tanzanite and are actually man-made. They are created not on purpose, but as a consequence of the mining processes involved in extracting them. The metamorphic rock they are found in is very hard and dynamite is needed in order to blast through this rock to get to the 'boudins' (isolatedpockets the crystals are found in). The blasting is what causes the fractures.
This crystal comes with an old 'Delrosario Collection' label as well as an acrylic display case.
