Underground crystal, to world-renowned rock star, Tanzanite’s story is an inspiring one for all undiscovered minerals. There’s no doubt that this gem has earned its super-stardom thanks to natural trichroic talents but the helping hand of manager Tiffany & Co is what brought Tanzanite jewelry overnight fame.
First discovered in 1967 by a Masai tribesman in Merelani, northern Tanzania, this fresh-faced gem was quickly picked up by Tiffany & Co who recognised the gemstone’s potential as a headliner and became the main distributor. Tanzanite is a variety of Zoisite, which is a member of the Epidote group, and owes its unique color to trace elements of Vanadium. Tanzanite’s color can vary from vivid blue to lavender purple but it’s this stone’s pleochroism that sets it apart from other similarly colored gems.
Pleochroism refers to a crystal’s ability to display different colors depending on the crystal axis it is viewed from. This optical phenomenon results in ‘differential selective absorption’ (where wavelengths of white light are absorbed differently due to a crystal’s internal chemical structure). Tanzanite is an orthorhombic crystal and displays trichroism, meaning it displays three different colors from three different crystal axes. Typically found in a yellowish-brown “bug-juice” color, the majority of blue Tanzanite’s on the market have been subject to heat treatment to cancel out the yellowish-brown tones and further enhance the blue/violet hues. Although it is possible to find naturally occurring blue crystals, it is extremely rare. Even still, these natural blue Tanzanites are still heated but from a mechanical geological action rather than a lab process. Unheated stones show trichroic colors of purplish red, blue and green/yellow, the green/yellow portion is not observed in heated stones. These results are a way of identifying heated and unheated stones.
Pleochroism influences a Tanzanite’s color and some faceted stones may show flashes of both blue and reddish purple when slowly tilted from side to side. This remarkable coloring attribute has helped it gain such quick popularity, rivaling the likes of the classic blue Sapphire. The challenge for stonecutters is to capture this amazing color play whilst still retaining carat weight and clarity when orienting the crystal for faceting. Vivid blue Tanzanite rings are the most desirable but as the blue color is viewed from the short axis of the crystal it is not the most economical orientation to cut from in order to gain the most yield out of the rough, and for this reason most Tanzanite gemstones exhibit a more purple/violet color.
Tanzanite can be found in eye-clean quality but it's known to have fine healed fractures, this along with a hardness of only 6 ½ (MOH’s scale), paired with perfect prismatic cleavage, make it a problematic mineral to cut and set. (Cleavage refers to a stone tendency to ‘cleave’ or ‘split’ along certain crystallographic structural planes due to a weakness in their atomic bonds).
Bunny Bedi, owner and designer at Made in Earth, has included this icon in his vast collection. “Tanzanite is found exclusively in Tanzania but luckily for us most tanzanite rough is being cut in India so we have access to stones. Although it’s common practice for tanzanite to undergo heat treatment it is still not a guarantee that all brown rough will produce the desired blue/violet color. We have found some bi-colored stones with yellow/green color zoning and although they are not ‘traditionally beautiful’, we’ve found them to be quite interesting specimens for our Tanzanite jewelry collection.”
Tanzanite is the new kid on the block but has made waves through the jewelry industry, gathering a worldwide following along the way. Its color is more complex than others in the ‘precious gemstone’ category and although tanzanite requires special treatment to showcase its true colors we can still appreciate its natural talents. Known as ‘the stone of magic’, you too can appreciate the magic of its beauty when viewing our range of Tanzanite pendants, rings, and earrings.
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