Some Tanzanites on your site are graded vB 6/5 and others bV 6/5 using the GIA system. What is the difference?
It is simply the axis on which the Tanzanite is cut. Tanzanite has 3 different colors in it – this is called trichroism and Tanzanite is one of the very few gemstones on earth that has this. You can learn more about this on this page of our site: Tanzanite History & Care and reading the “Amazing color in Tanzanite” section. When a piece of Tanzanite rough is cut with the blue axis facing upwards through the table, the stone will be predominantly blue with a violet modifier (the violet axis will be parallel to the blue) and the stone is graded vB (violetish Blue). When the reverse is true, and the violet axis is located upwards through the table then it is graded bV (bluish Violet) and is predominantly violet with a blue modifier. Whether a Tanzanite is more blue or more violet has no bearing on quality. What matters is the depth of color – how deep and vivid the color is. Here you look at the 2 numbers following – in the case of the Tanzanites on our site this is usually 6/5. The 6 rel
