June Birthstone – Alexandrite
Often described by gem aficionados as “emerald by day, ruby by night,” alexandrite is the very rare colour change variety of the mineral chrysoberyl.
Alexandrite is a relatively modern gem. Legends claim that it was discovered in 1834 on the same day that future Russian Czar Alexander II came of age, hence the name honouring him. Because this unique gemstone changed colours from green to red, the national colours of Russia, alexandrite became Imperial Russia’s official gemstone.
Alexandrite is a rare variety of the mineral chrysoberyl that changes colour from bluish green in daylight to purplish red under incandescent light. This chameleon like behaviour is the result of its uncommon chemical composition which includes traces of chromium, the same colouring agent found in emerald. The unlikelihood of these elements combining under the right conditions makes alexandrite one of the rarest and costliest of gems.
After Russia’s mine deposits were exhausted, the popularity of alexandrite waned until new supplies were discovered in Brazil in 1987. Brazil, Sri Lanka and East Africa are now the main sources for alexandrite, though these are not as vividly coloured as the original Russian stones.
With a hardness of 8.5 on the Mohs scale, alexandrite is softer than sapphire and harder than garnet, the other gemstones that can change colour. However, due to its scarcity, alexandrite is more valuable than most gems, even rubies and diamonds.
Associated with concentration and learning, alexandrite is believed to strengthen intuition, aid creativity and inspire imagination – bringing good omens to anyone who wears it.
Because it’s so scarcely available, fine quality alexandrite is practically unaffordable to the general public. Even lower quality stones are expensive and limited in supply.
Since the 1960s, labs have grown synthetic alexandrite – not to be confused with simulated alexandrite, which is actually corundum or coloured crystals infused with chromium or vanadium for colour. Creating synthetic alexandrite is an expensive process, so even lab-grown stones can be costly.
How to Buy Alexandrite
One of the rarest and most valuable gemstones, alexandrite is a luxurious present for lucky babies born in June. It’s also the traditional gift to celebrate a 55th wedding anniversary.
Colour change is the most important factor when determining alexandrite’s quality and value. The brighter the colours and the more dramatic the change from bluish green in daylight to purplish red under incandescent light, the more valuable the gem.
Like most gems (except its fellow June birthstone, the pearl), alexandrite is weighed in carats. Higher clarity may weaken the stone’s colour change, so colour is much more important than clarity in this case.