The name zircon comes from the Persian word “zargun”, which means gold-colored. Zircon occurs in a variety of colors including yellow, green, red, reddish-brown, grey and blue. Zircon is the oldest mineral found in the crust of the earth. Zircon is a durable gemstone rating a 7.5 on Mohs hardness scale. Zircon is a birthstone for the month of December, along with tanzanite and turquoise.