Gold Filled is an increasingly popular alternative to solid gold that consists of a layer of gold pressure that is bonded to a base metal. It differs from gold-plated in that it maintains its value better and is more tarnish-resistant. The improved value maintenance is because gold-filled pieces contain more volume (5%) of gold than gold-plated pieces. Its better tarnish-resistant property is due to the greater effectiveness of the pressure-bonding process compared to microscopic plating.