Panagias

Engolpion (Greek ἐγκόλπιον) is a general term for something worn upon the bosom; here, it refers to a medallion with an icon in the center. A Panagia (Greek Παναγία, All-holy, one of the titles of the Theotokos) is an engolpion with the Holy Virgin as the subject of the icon. Panagia is worn by all bishops. All primates and some bishops below primatial rank have the dignity of a second engolpion, which usually depicts Christ.
Istok Church Supplies offers excellent selection of jewelry panagias: enameled panagias, filigree panagias, gold-plated panagias, stone-rich panagias, and hand-made panagias. (Partial source: Wikipedia.)