This is very rare lot of natural green zircon with unusual gemological properties. Aside from the fact that green is an uncommon color for zircon, this material also reacts like singly refractive stones in the polariscope where zircon is supposed to be doubly refractive.
Natural zircon is often confused with cubic zirconia, a laboratory-grown diamond stimulant. Natural zircon and cubic zirconia are totally unrelated, zircon is a naturally occurring gemstone while cubic zirconia is a synthetic.
Zircon is known for its distinctive beauty and occurrence in a broad range of colors. It can be blue, green, colorless, brown, red, orange or yellow. The most popular color is blue and it is considered to be an alternative birthstone for December. Because of its similarity to diamond, colorless zircons have also been popular for years.