で 1830, a gem that changed color was discovered in the Ural Mountains in Russia, namely alexandrite. This day happened to be the birthday of Emperor Caesar Alexander II of Russia, so he named him Alexandrite after the Emperor of Russia. It was also called “アレキサンドライト” in the market.
The color of alexandrite changes with the change of the environment, enjoying the reputation of “emeralds in the day and rubies in the night”. It is the gem with the best color-changing effect among all the gems that can change color, だからそれはまた呼ばれます “アレキサンドライト”. As in the case of opals, only chrysoberyl alexandrite can directly call “アレックス”, and other gemstones with a discoloration effect must indicate their species.
The main producing areas of alexandrite are Russia, スリランカ, ブラジル, Madagascar and Tanzania, and the only producing area of alexandrite that can produce cat-eye effect is Sri Lanka.
The quality evaluation of alexandrite is mainly based on color, 明確さ, 透明性, cut and quality.
(1) 色. The color evaluation of alexandrite is more complicated, not only requires pure body color, the greener the better under sunlight, the redder the better under light, and the color change effect is obvious, and the two colors have a greater contrast. It is also rare to find a chrysoberyl alexandrite that is emerald green in sunlight and red in light.
(2) Clarity and transparency. Alexandrite is the same as a gemstone of the golden emerald group, with good clarity and transparency. Because alexandrite is so precious, even if there is a little problem, it is also very valuable. Cat’s eye alexandrite is translucent to slightly transparent.
(3) Cut work. After being cut into faceted gemstones, alexandrite can produce strong brightness and good luster. したがって, the cutting is required to be as perfect as possible. For alexandrite with a cat’s eye effect, it should be cut into a curved gem.
(4) 品質. 0.3~0.4 ct are mid-range products, and the price of high-quality products weighing several carats can be comparable to emeralds and rubies.
Alexandrite has good hardness and toughness. It can be cleaned with an ultrasonic cleaning machine. Avoid high temperature, 衝突を避ける, and store it separately to prevent damage.