Nacre, commonly known as mother-of-pearl, is a smooth, iridescent substance produced by certain mollusks, such as oysters and abalone. It forms the inner layer of their shells and serves as a protective lining against parasites and damage. Nacre is composed of aragonite, a form of calcium carbonate, and organic materials, which give it its unique luster and strength. In addition to its natural beauty, nacre is used in various decorative items, jewelry, and inlays. Its shimmering appearance makes it a popular choice for artisans and designers. Nacre is also studied for its structural properties, inspiring innovations in materials science and engineering.