Alexandrite is a very rare ‘colour-change’ variety of the mineral chrysoberyl. It was originally found in Russia’s Ural Mountains in the 1830s and is now also mined in Sri Lanka, East Africa and Brazil.
It was named after Tsar Alexander II because it was discovered on his 16th birthday. Due to the tsarist colours of red and green, it was previously known as Russia’s national stone.
The manner in which this gemstone absorbs light has lead to Alexandrite being known as ‘emerald by day and ruby by night’. This colour variation phenomenon is known as ‘the alexandrite effect’. This gemstone ranges from mossy green, hints of blue, raspberry red to amethyst purple. Chromium element is responsible for its colour.
High quality Alexandrite has very few inclusions. Clean gemstones with good colour change and strong colours are hugely in demand and this has lead to a rise in value. Thin inclusions oriented parallel to each other create a phenomenon known as ‘chatoyancy or the cat’s-eye effect’ and this increases its value.
Alexandrite is mostly shaped to produce mixed cuts which feature brilliant-cut crowns and step-cut pavilions. A kite shape and triangular facets are depicted in the brilliant-cuts and concentric rows of parallel facets are seen in the step-cuts.
Alexandrites tend to be small in size, generally below one carat. Prices rise steeply with larger sizes and better qualities.
Alexandrites are not commonly treated although there have been reports of oil and resin based fracture filling used in Alexandrites. We believe in full disclosure of any treatment that a stone has undergone.