These earrings feature a AAA grade Australian opal with white nacre (Mother of Pearl) and gold half moon. They are made with gold fill and feature an optional jacket hoop (which is symbolic of the orbit of moons around their planets). This hoop can be worn in front or behind the earlobe. The earrings can also be worn without the hoop, as studs, as well. Care: gently clean with warm soapy water and a toothbrush. Please avoid using chemicals or ultrasonic cleaners on these.