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LOT 33347107

Very Rare Transparent Alexandrite Crystal Color Change 14.880ct - 21.72×11.5×6.72 mm - 2.976 g

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Stone: Rare Natural Transparent Alexandrite Rough Weight: 14. 880 ct Dimensions: 14. 77 x 8. 39 x 6. 38 mm Shape: Natural Clarity: Transparent - translucent Colour: Colour change (nice green changes to purple) Origin: Lake Manyara, Tanzania Treatment: NONE 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.

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Germany
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Stone: Rare Natural Transparent Alexandrite Rough Weight: 14. 880 ct Dimensions: 14. 77 x 8. 39 x 6. 38 mm Shape: Natural Clarity: Transparent - translucent Colour: Colour change (nice green changes to purple) Origin: Lake Manyara, Tanzania Treatment: NONE 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.

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Time, Location
10 Jan 2020
Germany
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