Seashell

Description

A hard outer covering of a mollusk. Seashells are composed primarily of calcium carbonate (aragonite) bound with chitin. Some seashells, such as abalone, pearl oyster and mussel, have a hard iridescent inner layer. The iridescence is caused by the interference of light waves reflected between the thin overlapping layers. Seashells are soft and easily cut or carved. They have been used for beads, amulets and decoration since ancient times in both Eastern and Western cultures.

Synonyms and Related Terms

sea shell; nacre (Fr.); oyster shells; concha marinha (port.);

Authority

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• Oppi Untracht, Jewelry Concepts and Technology, Doubleday & Co., Inc., New York City, 1985

• Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982

• A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998