Zircon is an important gemstone of many colors, and is an historical gemstone used for thousands of years. It is sometimes looked upon as a cheap Diamond simulant, but in actuality it can be a valuable gem. Colorless zircon is well known for its brilliance and flashes of multicolored light, called fire. These two zircon properties are close enough to the properties of diamond to account for centuries of confusion between the two gems. Zircon occurs in an array of colors. Its wide and varied palette of yellow, green, red, reddish brown, and blue hues makes it a favorite among collectors as well as informed consumers. Zircon crystals grow in many different types of rock and possess a range of optical and physical properties.