Alexandrite is one of the world’s rarest stones, and is characterized by its unique colour-change phenomenon. The gem’s colour depends on the type of light that shines on it – candle light gives the gem a pink or red glow, whilst daylight renders it green. This spectacular property has created the term ‘The Alexandrite Effect’ which is now used to communicate a gem which changes hue. The level of the colour change depends on the amount of yellow and blue light the stone absorbs. Typically, the stronger the colour change; the more precious the stone.
Alexandrite, photographed in daylight (left) and candlelight (right)
COLOUR, CLARITY & CUT
The Alexandrite’s depth of colour change is its most important characteristic. The world’s best examples change hue from a light blue green to a purplish – or sometimes pinkish – red. The depth of this change in colour is given a percentage – a 100% colour change, considered the “Holy Grail” of Alexandrite, is the ideal colour change percentage.
Stones which only hold a colour change percentage of 30% or less are generally not of great interest to collectors and Jewellers. In addition, stones with significant grey or brown elements considerably lower the value.
Alexandrite is often compared to Ruby in terms of its clarity. Clean, well faceted gems in sizes above one carat are rare; whilst those ranging from 2 – 3 carats are very rare and worth considerable interest.
Gems can be found in a variety cuts and shapes, with the classic oval shape being the most common.
As one of the world’s most expensive gemstones, Alexandrite can fetch prices similar to an Emerald or Ruby, like all gems around the world, low quality varieties can be found and can be purchased for only a few dollars per carat – but cannot be considered gem quality. Visit our dubai online shopping and we can give you the right information about the value of Alexandrite and about any other gold stones.
ORIGINS & IMITATIONS
Russia is famed as the original locality for this gemstone, fine specimens of Alexandrite have also been found in Brazil, Tanzania, Sri Lanka and India.
A note on imitations: While synthetic Alexandrite stones can be purchased, the majority of these synthetic stones are in fact synthetic Sapphires with a vanadium coating. Yet as these synthetic sapphires have been produced as early as the 1910s, you can purchase a synthetic stone that can almost be classed as an antique.
NAME, FAME & LEGEND
Legend has it Alexandrite received its name in honor of Alexander II, the former Russian Tsar. Coined by mineralogist Nordenskjöld, many believe that Alexander turned 18 when the stone was discovered – in 1830 on the 23rd of April.
Another factor at play is the fact that the two colours of Alexandrite – red and green – are the champion colours of Imperial Russia.
ALEXANDRITE GEMSTONE PROPERTY
|Refractive Index||1.746–1.755 (0.009) Biaxial positive|
|Colors||Daylight: Green to blue-green
Incandescent Light: Purple to purplish red
Alexandrite is colored by the same Cr+3 ion that gives Ruby and Emerald their rich hues. Rarely, vanadium may also play a part.
|Pleochroism||Strongly trichroic: greenish, reddish and yellowish|
|Phenomena||Change of color, cat’s eye|
|Handling||No special care needed|
|Enhancements||Generally none; occasionally oiling, dying|