An ornament made from a shell is a popular decorative item. The two most common types of shells used for this purpose are ABALONE and CAMEO. ABALONE is a type of mollusk with a colorful, iridescent shell that is often used to make jewelry and other decorative items. CAMEO is a type of shell carving in which a raised design is carved into the surface of the shell. Both ABALONE and CAMEO shells are popular choices for creating beautiful and ornamental pieces.