I have a special gemstone which is a Tanzanite from Tanzania. This piece is unimaginably rare because change from purple blue to some green. This phenomenon is called pleochroism. Quality of this Tanzanite is exceptional.Stone is perfect terminated from all sides. tanzanite crystal with sharp termination, classic colors, transparency and strong lustre! The pleochroism for which these rare gems are known for is clearly visible; violet color along one axe and deep blue along the other and red among de c-axe! Approximately 1000x rarer than diamond..Mined only at 1 location in the world within a few square km. On average, it took 500 million years to form a tanzanite crystal Increasingly scarce and an export ban on raw crystals is in effect.