Be careful not to confuse zircon with synthetic zirconium oxide!
Zircon is a zirconium silicate which during extraction has a dark brown, green or red color and changes color when heated. Most blue stones are pastel blue, but some exceptional gems have a bright blue color.
Zircon is also available in green, dark red, purple, yellow, brown and orange. Due to its high refractive index and high dispersion, zircon has great brilliance and intensity.
Zircon is found in Australia, Brazil, Cambodia, Madagascar, Mozambique, Myanmar, Niger, Korea, Sri Lanka, Tanzania, Thailand and Vietnam.