White Mother of Pearl / MOP 18-22mm rectangle carved beads (ETB00370)

White Mother of Pearl / MOP 18-22mm rectangle carved beads (ETB00370)

Size: 19 x 29 x 4 mm
- they can carry small variations.
Length: 16 inches

Mother of pearl, is an organic-inorganic composite material produced by some molluscs as an inner shell layer; it is also what makes up the outer coating of pearls. It is strong, resilient, and iridescent.

Mother of Pearl is found in some of the more ancient lineages of bivalves, gastropods, and cephalopods. However, the inner layer in the great majority of mollusc shells is porcellaneous, not nacreous, and this usually results in a non-iridescent shine, or more rarely in non-nacreous iridescence such as flame structure as is found in conch pearls.
The outer layer of pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. Other mollusc families that have a nacreous inner shell layer include marine gastropods such as the Haliotidae, the Trochidae and the Turbinidae.

The main commercial sources of mother of pearl are the pearl oyster, freshwater pearl mussels, and to a lesser extent the abalone. Widely used for pearl buttons especially during the 1900s, were the shells of the great green turban snail Turbo marmoratus and the large top snail, Tectus niloticus.