as jewelry evolved from the pictorial coin worn on a chain or brooch. Coins and medals with high artistic standards were already minted in ancient times.
Lockets were and are designed in a variety of shapes, they can be round, oval or heart-shaped, etc. They are usually made of precious metals, often they are set with precious or semi-precious stones or enamelled inlays and pearls or enamelled. Medals are hinged so that they contain a thumbnail, photo, or other memento such as a gift. a lock of hair.