Shells

While a shell is defined as "a hard, rigid outer layer, which has evolved in a very wide variety of different animals including mollusks, sea urchins, crustaceans, turtles and tortoises, armadillos, etc" the most familiar "shells" are seashells.

Scientifically speaking, seashells are the external shells of marine mollusks. They are usually mostly made of calcium carbonate. This make-up can take different forms, one being nacre or mother of pearl.

Shells of many types were, throughout prehistory, history and are still to the present day, popular as human adornments, either used whole or cut into pieces. The uses have including all kinds of pendants, beads, buttons, brooches, rings, and hair combs.

Additionally, shells are commonly used in home decorating. Small pieces of colored and/or iridescent shell have been used to create mosaics and inlays to decorate larger items such as boxes and furniture. Also, large numbers of whole seashells, arranged to form patterns, have been used to decorate man-made grottos.