Alexandrite and some of its properties.
Alexandrite is exotic and enchanting. Its ability to change colour from sensual glowing greens to deep reds is subtle and beguiling. Once you have noticed it, it will take hold of you and stimulate your senses.
Alexandrite is a rare variety of chrysoberyl and is prized for its remarkable optical properties. In natural daylight, which is rich in shorter wavelengths, it looks bright green. In the warmer longer-wavelength light of candles or light bulbs, it takes on a rich red or brownish-red colour. It has therefore been described as an Emerald by day and a Ruby by night.
The colour change is due to chromic oxide. This in Alexandrite partially replaces the aluminium oxide that occurs in the chemical composition of chrysoberyl. Colour changes do occur in some types of Sapphire, Tourmaline, Apatite and many other gemstones, but in this gemstone it shows the most dramatic effect.
An important source of Alexandrite was the Ural Mountains of Russia, where the variety was first described in 1830. The story has it that it was discovered by emerald miners on the birthday of Tsar Alexander ll and was named in his honour. The name was doubly appropriate since red and green were the Russian imperial colours.
The gemstone became very popular in Russian jewellery and the Urals mines were soon exhausted. In the 1920s Tiffany produced some beautiful rings with Alexandrite set in platinum.
For much of the 20th century, with no major discoveries of the mineral, Tis gemstone was extremely rare. Then in 1987 a new find was made in Brazil. This had a dramatic colour change from raspberry red to bluish green. Then in 1993 there were further large finds of it on the boarder of Tanzania and Mozambique and in Sri Lanka.
Care must be taken when working with Alexandrite as it is sensitive to knocks, and colour changes are possible with exposure to great heat.
High-quality Alexandrite is one of the most expensive of all gemstones.
The largest stone, weighing 1876 carat, was found in Sri Lanka. The largest cut Alexandrite from Russia weighs 66 carat and it is in the Smithsonian Institute in Washington DC. Many gemologists still believe a fine example, known undisputedly to have come from Russia, is a real rarity with enormous value.
The number one criterion in valuing Alexandrite is the amount of colour change, combined with its clarity and size. Generally speaking, cloudy Alexandrites have more chance of a stronger colour change than clear ones. However if you can find one that has a clean crystal structure and a vivid colour change then you are looking at a very rare gem.
Alexandrite is one of the three birthstones for the month of June, (particualy in the USA) together with Pearl and Moonstone. It is used as the gemstone to celebrate the 45th wedding anniversary. It is the birthstone for females with the name Alice and males with the name Alexander.
Alexandrite is believed to strengthen the wearer’s intuition, and thus find new ways forward where logic and practical thinking will not provide an answer.
It is known to aid creativity and inspire one’s imagination.
In France and England, during the 18th century, rings, bracelets, brooches etc. were often set with gems, the first letters of which, when combined, formed a motto or expressed a sentiment. Alexandrite was used to express Faith, Regard and Dearest, together with the Greek word meaning Forever.
This is a gemstone which, if of good quality, should increase in value as time goes by.
Below are some examples of the colour change under different lighting of the same piece of jewellery.