Alexandrite

Gem, first found in the Urals in 1830, on the day of maturity Prince Alexander II, was named after him.
In chrysoberyl, the third strength after diamond and corundum gemstone, there are two valuable varieties: alexandrite and cat's eye. The latter, which usually has a cold gray color, not to be confused with the much less valuable quartz cat's eye.
Rare stone
Alexandrite - the most rare type of chrysoberyl. It is a transparent or translucent mineral, forming flat crystals or twins. These crystals are found among the metamorphosed ultramafic rocks of surface and on alluvial deposits.
Change color
Depending on the light alexandrite changes color. In daylight it is emerald green or light because of the impurities of chromium, aluminum zameschayushih during the formation of the mineral. Under artificial light becomes purple or magenta. Also, the color of alexandrite can vary from red to yellow-orange depending on the angle at which it is viewed. This property he has to chromium and iron.
DPJ stones those who understand
So called experts gems three varieties of chrysoberyl: directly chrysoberyl cat's eye and alexandrite.
Chrysoberyl
Is yellow, yellow-green, green and yellow-brown in color, due to iron impurities. Mined in Brazil and Sri Lanka.
Cat's Eye
Of all the stones to the effect of "cat's eyes", this is the most beautiful. On the soft green or brown-gold background swims almost brilliant blue stripe resembling narrow cat's-eye.
Alexandrite
This is the most valuable of the three species. Thanks chromium alexandrite changes color depending on the light.
A rare and mysterious stone
Alexandria - a rare gem. It is produced by artificial means, but it is not for sale and for use in the aerospace industry.
Net alexandrite, pleasing eye shimmering light, is extremely rare. Stones of good quality and size are more expensive rubies and sapphires. With the exception of museum exhibits raw, whole alexandrite is cut. Since this stone is extremely hard, and in aggregated form, it takes an extraordinary brilliance and liveliness faces.
Famous examples
In Moscow the Mineralogical Museum of. Fersman is the most beautiful group of twins alexandrite 22 crystal, the largest of which has a size of 6x3 cm is also widely known two stones from Sri Lanka 43 and weighing 27.5 carats, are stored in the Natural History Museum in London, and the largest process instances of alexandrite in 66 carat - at the Smithsonian Institution in Washington. The largest stone is mined in Sri Lanka and weighs 94 carats.
Imitations
In Europe and North America to make quality imitation alexandrite. In the manufacture of such simulations typically use synthetic corundum, spinel, green glass.
Gem for high technology
There is nothing strange in the fact that Alexander is often surrounded by mystery. Production alexandrite so expensive that its production for resale does not make sense. However, it is produced with a different purpose. This stone filters out a certain part of the solar spectrum and is used in the manufacture of laser systems (top) and portholes satellites. And the challenge clear, transparent synthetic alexandrite cope better than natural.
Where seen alexandrite
Highest quality alexandrite mined in Tanzania. The richest deposits are located in Brazil and Sri Lanka.