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Violet Blue Tanzanite

Tanzanite is a rare violet-blue form of zoisite, a mineral that was recently discovered in 1967. Tanzanite earned its name after being discovered in Tanzania, Africa. To this day, East Africa remains the only source for tanzanite and the supply of high grade gem specimens is quite limited.

Tanzanite is a gorgeous gemstone and so the immense popularity of tanzanite is not surprising at all. Originally the gem was known by the more pedestrian name, "blue zoisite", but tanzanite is rarely blue in nature. In its natural state, Tanzanite is a rather common shade of brown, and the violet blue is produced through low level heat treatment. Tanzanite can be quite delicate and soft compared to other hard-wearing gems. In fact, tanzanite's hardness level is actually very similar to emerald; it is rated a 6.5 - 7 on Mohs scale and possesses delicate cleavage. Despite being delicate in comparison to other gemstones, it is still more durable than steel (slightly softer than quartz), and the rich color of Tanzanite is so unique that it can only be rivaled by the finest blue sapphire.

Despite its natural beauty, not all Tanzanite is considered exceptionally valuable. The determining factors of value are like that of all gems -- color, clarity, cut and carat.  However, in the case of Tanzanite and colored gemstones, color is often regarded as being the most important factor, outweighing almost all the other considerations. Tanzanite is classified to be a ‘Type I’ gemstone by GIA (Gemological Institute of America), distinguishing that Tanzanite is normally eye clean. Thus, clarity is rarely an issue reported with Tanzanite. Tanzanite can occur in gold, green, violet and blue, leaving a very wide color range to evaluate.  Color saturation levels can also be quite varied, with some stones being quite pale and others being preferentially deep.

Evaluating the grade of tanzanite is extremely important, but unfortunately there isn’t a straight-forward approach or standard used for Tanzanite grading. Since people often refer to "Triple A" or "Double A" grade tanzanite, this may come as a bit of a surprise, but these terms do not carry any official definition with the gem trade. Without a doubt, the largest producer of tanzanite is a company called TanzaniteOne. TanzaniteOne introduced a unique color grading scale in partnership with a well-known non-profit subsidiary, known as the Tanzanite Foundation. They graded gem color using standard terms, such as "exceptional", "vivid", "intense", "moderate", "light" or "pale" and described color as being "violet-ish blue" or "bluish violet".

Since there is no way to accurately determine the difference between "exceptional" and "vivid", TanzaniteOne’s grading scale is very unlikely to be adopted by gemological laboratories. Despite technicalities, one virtue of this grading evaluation scale is that it does aid in distinguishing why certain colors are graded above others. Generally, tanzanite is more valuable when its color leans towards blue as opposed to violet and when the color is more saturated. Although many buyers do prefer violet-ish colors, or lighter tones, deep blue tanzanites will command the highest prices in the market.

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