Carbuncle (heraldry)

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.