Stone: Rare natural alexandrite rough
Weight: 10.670 ct
Dimensions: 11.95 × 8.40 × 6.35 mm
Clarity: Transparent - translucent
Colour: Iridescent colour (nice change between green and purple)
Origin: Lake Manyara, Tanzania
This rare gemstone is named after Russian tsar Alexander II (1818-1881), the very first crystals having been discovered in April 1834 in the emerald mines near a river in the Ural Mountains. The discovery was made on the day the future tsar came of age. Although alexandrite is a relatively young gemstone, it certainly has a noble history. Since it shows both red and green, the principal colours of old Imperial Russia, it inevitably became the national stone of Tsarist Russia.
Alexandrite is very scarce: this is due to its chemical composition. It is basically a chrysoberyl, a mineral consisting of colourless or yellow transparent chrysoberyl, chrysoberyl cat’s eye and colour-changing alexandrite (also in cat’s eye varieties). It differs from other chrysoberyls in that it not only contains iron and titanium, but also chromium as a major impurity. And it is this very element which accounts for the spectacular colour change. Rarely, vanadium may also play a part. According to CIBJO nomenclature, only chrysoberyls displaying a distinct change of colour may be termed alexandrite.
- Main Mineral/ Name Meteorite
- Very Rare Large Alexandrite Crystal Color Change
- Mineral Form/ Type Meteorite
- 15.49×10.39×9.9 mm
- 2.134 g
- Origin (Region/ City)
- Lake Manyara
- Origin (Country)