Tanzanite belongs to a more recent kind of gemstone, only awakening curiosity and attracting attention during the second half of the 20th century. Its original family, zoisite, has long been known by geologists, but the sensational discovery of this blue gem-quality relative was only made in 1967. As its name unmistakably reveals, Tanzanite was first unearthed in Tanzania, near Arusha, not far from Mount Kilimanjaro.

Often barely distinguishable from a blue sapphire, tanzanite occurs in the finest blues imaginable. In its original state, this African gem exhibits strong pleochroism – its colour varies between reddish-purple, blue, and deep purple depending at which angle the stone is viewed. It can also display brown, grey and even green. In order to remove the less desirable purple and brown shades and bring out a radiant blue, professional heating is applied to the gem.


Initially the colour behaviour of tanzanite was attributed to tiny quantities of strontium. After extensive chemical analyses carried out by Dr. Eduard Gubelin at the University of Zurich, the true cause of tanzanite’s colour varieties was determined to be traces of vanadium in the gem’s chemical composition. This finding increased the exciting rivalry between blue sapphire and tanzanite.


Gemmological Properties
Tanzanite is the blue variety of zoisite, a colourful family encompassing a variety of minerals that tend to be classified as more modest gems. Zoisite is a silicate of calcium and aluminium.


Mining Areas
Whilst all other zoisite varieties are found worldwide, tanzanite of gemstone quality is found only in Tanzania, buried in the foothills of Mount Kilimanjaro. Kenya and Pakistan are unconfirmed sources of tanzanite.