Brilliant 5mm rounds of blue zircon are cradled in four-prong settings of polished 18 karat yellow gold to create these striking stud earrings. Blue zircon is a beautiful naturally occurring pastel-to-bright-blue gemstone that is heat treated to enhance its color. Zircon is sometimes confused with cubic zirconia, a lab-created stone, because of their similar sounding names. But zircon is in fact a gorgeous natural gemstone, with a high refractive index that gives it a tremendous diamond-like sparkle. In its lighter shades, it may resemble aquamarine, while in its brighter shades it can be compared to a blue topaz or a blue diamond. Blue zircon is considered an alternate birthstone for the month of December. These luxurious earrings are featured on 18 karat yellow gold posts and fasten with butterfly friction backs.