Gold fill (also called gold overlay or gold-filled) is made by using heat and pressure to apply a layer of karat gold to a base of less costly metal. This produces a surface with karat gold. The minimum layer of karat gold must equal at least 1/20 of the total weight of the item. Gold-fill items are normally stamped 12kt GF or 14kt GF.
The color of Gold fill beads lasts much longer than the surface of gold plated beads (many years or even decades of frequent wear), because it is 50 to 100,000 times thicker than normal gold plating, and 17 to 25,000 times thicker than heavy gold electroplate (sometimes stamped 14kt HGP).