What is Alexandrite

So what exactly is this magical, colour changing gemstone alexandrite? Alexandrite is actually a rare form of the mineral chrysoberyl, which is the third hardest gemstone in the world. Only diamond and corundum are harder than chrysoberyl, and chrysoberyl also produces a static charge when it is rubbed that the stone can retain for as long as a couple of hours. Because of the hardness of this gemstone, all the forms of chrysoberyl, including alexandrite, are great to use in jewelry because they are so sturdy and durable. The unique quality of alexandrite is its wonderful ability to change from one well-defined colour to another depending on whether you are looking at it in natural daylight or under artificial light. Alexandrite is also a strongly trichroic stone and will display different colours depending on which direction you are looking at the gemstone from. A typical alexandrite can be a bluey-green colour in daylight and then change colour under incandescent light to a rich red/purple colour, with the most prized alexandrite gemstones showing the most vibrant, deep colour changes. In fact, alexandrite has lead to the new adjective ‘alexandritic’ being coined, which is a description for any transparent gem that shows a distinct change in colour when viewed in natural and then in artificial light.
Valuing Alexandrite

A fine alexandrite is going to be an expensive purchase. Large alexandrite gemstones are extremely rare, and an alexandrite weighing more than 2 carats that has been well cut, is a good colour and displays an intense colour change is probably going to cost you more to buy than a similar weight diamond. Alexandrite is classed as a Type II gemstone, so clarity is also important, although you would expect some eye-visible inclusions, but not enough to detract from the beauty of the stone. As has already been said, color is very important in determining the value of an alexandrite and also the depth of the color change. If you see a stone labelled as alexandrite that colour changes from green to yellow, it is more likely to be the less valuable colour change chrysoberyl, as true alexandrite should show a colour change of blue/green to red/purple. So care needs to be taken when purchasing alexandrite jewelry and you should always buy from a reputable dealer and obtain a gemological certificate from a recognised gem laboratory.
Where Does Alexandrite Come from?

Although alexandrite was first discovered in the Ural Mountains of Russia and most of the world’s alexandrite was mined there during wholesale costume jewelry the 19th century, very little alexandrite now comes out of Russia. This makes Russian alexandrite very prized; as if you have one it is likely to be a valuable antique stone. Alexandrite has more recently been found in Sri Lanka, Brazil, Myanmar, India, Western Australia, Madagascar, Zimbabwe and Tanzania, but none of these countries are producing large quantities of alexandrite. Probably the finest alexandrite produced today is being extracted from the Hematita Mine in Brazil, and the largest amounts of stones are being produced in India.