A carbuncle or escarbuncle is a heraldic charge consisting of eight radiating rods or spokes, four of which make a common cross and the other four a saltire. The ends typically terminate in a fleur-de-lis or some other decorative form. Frequently the centrepoint is adorned with a jewel; the name may therefore be a reference to a carbuncle gemstone.
It has its origins in the iron bands and bosses historically used to strengthen shields. The name may therefore be derived from the Old French boucle, meaning a shield boss.
Arms of Geoffrey de Mandeville, Earl of Essex and Gloucester: Quarterly Or and gules, an escarbuncle sable.
Arms of the town of Louvil in France: Gules, an escarbuncle Or pierced vert.
Arms of the Duke of Cleves in Germany: Gules, an escutcheon argent surmounted by an escarbuncle Or.