Alexandrite, Sri Lanka
Fondly known as an ‘Emerald by Day and a Ruby by Night’, Alexandrite is a type of Chrysoberyl that is rare yet abundantly found in Sri Lanka. Their ability to shift colours from red to green when viewed under different light sources makes Alexandrite a highly sought after gemstone in the global market. A strongly pleochroic gem, which displays different colours when viewed from different directions, the three pleochroic colours of Alexandrite are green, orange, and purple-red.
However, the gem's colour change doesn’t arise from the gem’s pleochroism, but from the mineral’s unusual light-absorbing properties. Although most Alexandrites found in Sri Lanka can be faceted, there is an occasional occurrence of colour changing alexandrite cat’s eye.