Zircon

Colourless zircon is known for its brilliance and flickers of multi-coloured light, called fire. These zircon characteristics are close enough to the properties of diamond to account for centuries of confusion between the two gems. Zircon occurs in a vast range of colours including yellow, green, red, brown, and blue hues, making it a favourite among collectors. It is a birthstone for the month of December, along with turquoise and tanzanite.