Preciosa Nacre Cabochon or Button pearls are flattened to some degree, making them resemble a button or perhaps a disk rather than a perfect sphere. These pearls are often used in earrings where the flattened side can be attached to the setting. Buttons are also categorised as symmetrical. These Pearls are Created to look and feel like the real thing, Preciosa Nacre Pearls contain a crystal core coated in several layers of nacre which gives them their signature silky-smooth finish.