Aurore Boreale Crystal Heart Earrings For the graduation girl who is seeking her path...these adorable rainbow crystal heart earrings will light her way as she finds her joy. Approx 1/2" long. On sterling silver, lead-free, nickel free wires. Aurore Boreale is a coating on top of clear crystal that gives it a "rainbowy" effect. Depending on how the light hits the crystal, beautiful shades of blue, pink & green shimmer and shine.