The SWAROVSKI ELEMENTS 5821 Pear Shaped Pearls have a crystal core that makes them heavier and more durable than synthetic glass pearls. Layers of luminous scratch resistant pearlescence are added to give SWAROVSKI ELEMENTS Crystal Faux Pearls the luster and shine of a real pearl. They are also resistant to perspiration, UV rays, perfumes, scratches and washing and they warm to the skin like real pearls do.