|This article does not cite any references or sources. (October 2011)|
Gold-filled jewelry, also known as "rolled gold" or "rolled gold plate" is composed of a solid layer of gold bonded with heat and pressure to a base metal such as brass. Some high quality gold-filled pieces have the same appearance as 14 karat (58%) gold. In the USA the quality of gold filled is defined by the Federal Trade Commission. If the gold layer is 10 kt fineness the minimum layer of karat gold in an item stamped GF must equal at least 1/10 the weight of the total item. If the gold layer is 12 kt or higher the minimum layer of karat gold in an item stamped GF must equal at least 1/20 the weight of the total item. The most common stamps found on gold-filled jewelry are 1/20 12kt GF and 1/20 14kt GF. Also common is 1/10 10kt. Some products are made using sterling silver as the base, although this more expensive version is not common today. These standards are for modern gold-filled items. It is not uncommon to see 1/8 14kt cold-filled marks, plus many other variations, on items from the 1930s, 1940's, etc., which would have to be marked "Rolled Gold Plate".
"Double clad" gold-filled sheet is produced with 1/2 the thickness of gold on each side. 1/20 14Kt double clad gold-filled has a layer on each side of 1/40th 14Kt making the total content of gold 1/20. The thinner layer on each side does not wear as well as single clad gold-filled.
The Federal Trade Commission allows the use of "Rolled Gold Plate" or "R.G.P". on items with lower thicknesses of gold than are required for "gold-filled." A 12 kt gold layer that is 1/60 the weight of the total item is designated as 1/60 12kt RGP. This lower quality does not wear as well as gold-filled items.
Gold-filled items, even with daily wear, can last five to 30 years but will eventually wear through. The gold layer on gold-plated jewelry varies greatly depending on manufacturer, so there is no single, simple comparison. Gold-filled items are 50 to 100,000 times thicker than regular gold plating, and 17 to 25,000 times thicker than heavy gold electroplate (sometimes stamped HGE or HGP—usually found on cubic zirconia "cocktail rings").