18k gold plated.hypoallergen I just LOVE THESE! Front back that can be exchanged for regular backing which I will include as a free gift. Will look fantastic with blouse, tank, t-shirt, skinny jeans shorts, mini shorts, mini skirt, skirt, cardigan, heels, stilettos, flats, sandals, sweater, blouse anthropology, free people, asos, Topshop, zara, MICHAEL kors, bralette, bodysuit, bodycon, bikini, necklace, hat, gloves, bra, lipstick, eyeliner, eyeshadow, vintage, jacket, scarf, romper