Alexandrite, a rare variant of the mineral chrysoberyl, is revered for its exceptional color-changing ability. This gemstone, under natural or fluorescent light, exhibits a mesmerizing green hue. However, incandescent light like that from a lamp or candle flame transforms its color to a brownish or purplish red. This unique phenomenon, known as 'the alexandrite effect', is due to the complex manner in which Alexandrite absorbs light.
Despite its pleochroism, exhibiting different colors when viewed from varying directions, the striking color change is attributed to its unusual light-absorbing properties. Alexandrite is rather pricey due to its rarity, especially in larger sizes, and shares its June birthstone status with cultured pearl and moonstone.
The technical stuff: Alexandrite is a member of the Chrysoberyl family and crystallizes in the orthorhombic crystal system. It has a chemical formula of BeAl2O4. It has a hardness of 8.5 on the Mohs scale which makes it very durable for jewellery.
Alexandrite was first discovered in 1830 in Russia’s Ural Mountains and was named after Russia’s Czar Alexander II. The largest ever mined crystal was 1876ct and the largest cut stone is 66ct and now sits in the Smithsonian Institution, Washington DC. High quality Alexandrite is carat for carat one of the most expensive gemstones.