Now here is absolute monster of a Cambodian blue zircon! Loose natural blue zircons of this size and quality from Cambodia are super rare and this one is a real beauty. Definitely a king stone and would command center place in any collection. It is big, real big and the colour intense and vivid. It is a knock out stone, no two ways about it. Natural zircon also has a particular birefringence property which shows itself as a sort of facet doubling. You can see the effect in the pictures. Birefringence is a measure of a gem's double refraction (just to get a little technical) and every zircon has it and so do a number of other gemstones out there in the mineral kingdom. It is a completely natural phenomenon and adds to the unique beauty of this gem. This is highly recommended as an investment stone or one for the collector. A blue chip gem in every regard.