After a graft from a donor shell, together with a spherical bead, have been implanted into a recipient shell  to create the nucleus as an artificial irritant around which the nacre will deposit to form a perfectly round pearl, the seawater oysters (fig.) are placed in metal frames with nets or —alternatively— attached to strings.

These netted frames or strings are then hung from wooden racks, or in between poles, and placed in shallow coastal marine waters, such as lagoons, for about twelve to eighteen months, before they are ready to be harvested.

The pearls are formed within the shell of the oysters, and are produced in reaction to the irritant within the soft tissue of the mollusk, which will secrete thousands of very thin concentric layers of nacre, and is the same composite material mollusks use to produce their inner shell layer, which is commonly known as mother-of-pearl.