MOTHER OF PEARL

Nacre, also known as mother of pearl, is a naturally occurring organic-inorganic composite. Nacre is secreted by the epithelial cells of the mantle tissue of certain species of mollusk. In these mollusks, nacre is continually deposited onto the inner surface of the animal's shell (the iridescent nacreous layer, commonly known as mother of pearl), both as a means to smooth the shell itself and as a defense against parasitic organisms and damaging detritus.

The iridescent inner layer is considered highly attractive by many cultures and is often used in making jewelery or as inlays in wood furniture and fret inlays for guitars.

When a mollusk is invaded by a parasite or is irritated by a foreign object that the animal cannot eject, a process known as encystation entombs the offending entity in successive, concentric layers of nacre. This process eventually forms what we call pearls and continues for as long as the mollusk lives.

Chief sources are the pearl oyster, found in warm and tropical seas, primarily in Asia; freshwater pearl mussels, which live in many rivers of the United States, Europe, and Asia; and the abalone of California, Japan, and other Pacific regions.

Both black and white mother of pearl are used for architectural purposes. The natural mother of pearl may be artificially tinted to almost any color.

Mother of pearl is also used to clad porcelain sinks. Mother of pearl tesserae may be cut into artistic shapes and be laminated to ceramic tile and surrounded by numerous coats of colored lacquer to create an artistic design. The lacquer and the mother of pearl are polished at the same time, creating a durable, glossy hard surface.

It is also available in thin laminated sheet form, allowing easy inlay and cladding work, and modern ceramic tiles. Shirt buttons were once often made of mother of pearl, though plastic has largely replaced its use. Some of the finer-quality clothing companies (e.g., Lacoste, Turnbull & Asser, and Hugo Boss) still use it. Mother of pearl is a popular style watch dial also found in Rolex watches.

Key touches and various decorations on musical instruments such as saxophones, trumpets, violins and guitars are sometimes made of mother of pearl. Synthetic key touches made of Pyralin or similar imitation materials have been affectionately referred to as mother of toilet seat by musicians.