Color Change Zircon oval cut

Well this is a zircon color change from Burma, those have been sold for a while and are still sold as untreated or unheated, this is not true; the color change zircon was heated by the people from Mogok by coincidence, a forest fire close to the surface where the zircons where buried caused a accidental heat treatment , so in the beginning the color change wasn’t linked to this event and where sold as natural. Nowadays clean zircons are heated on purpose! Most dealers nowadays know and therefore it shouldn’t be sold as untreated anymore. This stone shows a color swift from yellowish green in incandescent to bluish in daylight. Although it’s treated is fine stone with good luster and brilliancy.