Zircon is a semiprecious gem that comes in a variety of colors like yellows, greens, reds, and its most popular color, blue. Zircon is known for its spectral color flashes thanks to its exceptional fire. Because of its fire and its adamantine luster, Zircon is often cut with brilliant faceting patterns and often confused with diamond. Blue Zircon is one of several birthstones for the month of December and is a common 4th year anniversary gift.