Blue zircon has been traditionally used as a substitute for the far more expensive diamond for hundred of years. It is very similar –it is only slightly less hard (mohs hardness of about 7.5), and it has a similar luster and refractive index. It also has the brilliant sheen that the diamond is so famous for. However in the contemporary gemology, white zircon has been gaming importance in its own right. It is found in several other colors as well-brown, yellow , blue and orange being the most notable shades. Zircon is basically silicate. The mineral is found universally and in all types of rocks.