Zircon is not a very well-known gemstone, but it is one of the most important gemstones of today. Zircon occurs in a wide range of colors, of which white or colorless is likely the least valuable or important. The most popular zircon today is blue zircon, usually occurring with green pleochroism, which can result in interesting teal-like colors. Zircon can also be easily distinguished by its notable birefringence; when looking down through the table of a stone, the doubling effect of facet edges can be easily seen.In general, zircon is transparent to translucent. Impurities cause the various colors.