Was discovered at the Mererani mines of Tanzania in 1967.
In nature it occurs in quite a few colours, but most are heat treated to attain a beautiful violet blue colour, which is the colour that attracted interest in this gem when it was discovered. Although it is of adequate hardness, it is however somewhat fragile and ultra- sonic cleaning should be avoided!
Tanzanite is strongly dichroic, meaning it shows red-violet and deep blue depending on the direction viewed. It has been marketed quite fiercely; cheaper – pale colours are often sold on various TV shop channels. Conversely, supplies of actual good quality material are dwindling.