Markings on a ring that indicate "14k HGE" mean the ring contains 14-karat gold in "heavy gold electroplate," which indicates that the gold is not pure or solid gold but is a covering for some other metal. Normally, this layer of gold has a thickness between 7 and 100 millionths of an inch. Gold that is not marked with HGE can be tested electronically to discover its purity.
Gold electroplate is normally 10 millionths of an inch thick, and the layer wears off easily over time. This type of jewelry looks tarnished once the base metal is exposed. Hannon Jewelers explains that heavy gold electroplate reaches a maximum thickness of 100 millionths of an inch on top of base metal.
Rings electroplated with gold are not worth much to businesses that buy scrap, according to MintProducts. Rings marked "gold plated" or "gold filled" are the same as those that use heavy gold electroplate.
Electroplating is a process by which metals are bathed in a solution of the metal that covers the core object. The core metal is exposed to an electrical current, and the covering metal falls out of solution to gather around the electrolyzed core. The longer the core metal stays in the bath of gold ions, the thicker the gold covering gets.