Gold-filled is constructed in two or three layers. The core metal is jewelers’ brass. A gold alloy is then bonded to one or both surfaces of the brass core with heat and pressure. The bonded raw material is then sold as sheet or wire to jewelry manufacturers for use in designs.
Gold-filled is legally required to contain 5% or 1/20 gold by weight. This 5% is then described by the karatage of the gold alloy. Most gold-filled is 12kt or 14kt gold-filled. It is most accurately labeled with the karatage, the “/” symbol, and then 20 to reflect this construction. Products are identified as 14/20 Gold-filled or 12/20 Gold-Filled; alternatively, 14kt Gold-Filled or 12kt Gold-Filled are also acceptable.
STERLING SILVER 0.925
Sterling Silver is an alloy of silver containing 92.5% by mass of silver and 7.5% by mass of other metals, usually copper. The sterling silver standard has a minimum millesimal finesse of 925.