This refers to jewelry and other items where a layer of gold, specifically 18 karat gold, is applied over a base of sterling silver. Sterling silver, an alloy of silver containing 92.5% silver and 7.5% of other metals (usually copper), provides a durable and relatively inexpensive base. The 18 karat gold layer, composed of 75% pure gold and 25% other metals, imparts the rich color and luxurious appearance of high-karat gold without the associated cost of a solid gold piece.
This manufacturing technique allows for the creation of aesthetically pleasing jewelry at a more accessible price point. The combination leverages the durability and workability of sterling silver with the desirable visual properties of gold. Historically, this method has been employed to extend the reach of precious metals to a wider consumer base, enabling access to the look and feel of gold jewelry without the significant investment required for solid gold.