Zircon is a gemstone with a wide color range. A blue variety is sometimes called starlit, it is the most valuable. Such stones in color can resemble expensive Paraiba tourmalines. Another highly valued type has orange, brown or red color. Gem-quality zircons have unique optical properties, a strong birefringence effect and excellent dispersion, thanks to which a gemstone looks bright and memorable. They also come white, green, yellow, purple, and even with the phenomenon of color change.