gold filled | ˈgōld fild
adjective
A term for a piece made up of a base metal, coated in a thick layer of gold (at least 10k and 1/20th of the total weight of the piece) bonded to its surface
Gold-filled jewelry is more durable than gold-plated jewelry. With moderate to heavy use, both gold-filled and gold-plated jewelry will eventually lose their coating, leaving the base metal exposed.