GF, RGP, GE, HGE, Vermeil: How Much Gold Is Really There?

A watch chain marked 1/20 12K GF. A ring marked 18K HGE. A gold-colored bracelet stamped 925. Each of these marks contains a real gold number, and each is very easy to misread.

In this guide I'll show you what these letters mean, how much gold they actually promise, and how to do the little piece of arithmetic that tells you the truth about a gold-filled locket.

The big idea: gold on the outside

Between "solid gold" and "no gold at all" there's a whole staircase. On every step of it, makers put real gold on the outside, where it shows, and a less costly metal inside.

The FTC's Jewelry Guides define each step by two things: how the gold is attached (bonded on as a sheet, or deposited by electric current) and how much there is. For every one of these terms, the gold layer must be at least 10 karat.

Remember this one rule. The karat on a GF or RGP mark describes only the outer layer. "12K" on a gold-filled watch chain does not mean a 12K watch chain.

Gold filled (GF): the 2.5% arithmetic

Gold filled means a layer of gold of at least 10 karat, mechanically bonded to a base metal, where the gold layer is at least 1/20 of the total metal weight. You'll see marks like 1/20 12K GF, 1/20 14K G.F., 12K GF or GOLD FILLED.

The fraction is the layer's share of the weight. The karat is how pure that layer is. Multiply them, and you have the share of pure gold:

• The layer is 1/20 of the weight.
• 12K is 12 parts in 24, or one half gold.
• Half of one-twentieth is one-fortieth, which is 2.5%.

So a 10-gram "1/20 12K GF" locket (an example, not a real piece) holds about a quarter of a gram of pure gold. Gold filled is honest, durable work, and it can last a lifetime. But it is not solid gold, and it isn't priced like it.

Rolled gold plate (RGP) and gold overlay

Rolled gold plate and gold overlay are made the same way, with at least 10-karat gold, but the layer can be thinner. The Guides use 1/40 of the metal's weight for rolled gold plate, and give "1/40 12 Kt. R.G.P." and "14K R.G.P." as example marks.

The same arithmetic applies. For "1/40 12K RGP," one-fortieth times one-half is 1.25% pure gold by weight.

GE, GEP and HGE: electroplated gold

Gold electroplate is gold deposited by electric current. It may be marked GE, GEP, G.E.P., GOLD ELECTROPLATE or GOLD PLATED. The Guides set at least 0.175 microns of gold, about 7 millionths of an inch. (A micron is one-thousandth of a millimeter.) A layer that thin can wear through with use.

Heavy gold electroplate, marked HGE or H.G.E., must be at least 2.5 microns, about fourteen times thicker by our arithmetic.

Here's the misreading I most want you to avoid. People see "18K HGE" and read it as "high-grade 18K gold." It isn't. It's a base metal plated with 18-karat gold: a sturdy plating, but a plating.

Below these come gold flashed or gold washed coatings. The Guides say a piece shouldn't be called gold plated unless the gold covers all its significant surfaces with reasonable durability, so very thin coatings may carry no gold mark at all.

Vermeil: gold over silver

Vermeil (say ver-MAY) must be sterling silver coated with gold of at least 10 karat, at least 2.5 microns thick. If there's a layer of nickel under the gold, that must be disclosed. Vermeil is usually stamped 925 or Sterling, because the silver is the solid metal. So a gold-colored piece marked 925 is gold over silver.

What these marks can't tell you. How much gold is left after decades of wear and polishing. What the base metal underneath is. Whether a surface test can be trusted, because on these pieces the surface really is gold. And whether the piece is worth keeping: in 2018, Antiques Roadshow updated its appraisal of a group of Trifari "jelly belly" pins, made of gold-coated sterling, to $625 to $1,400 retail. Layered gold is not the same as worthless.

Volume I, Real or Fake?, sets out the whole staircase from solid gold to gold wash, explains where plating wears through first and how to spot it with a loupe, and covers every common gold and silver mark, so you can sort your family's pieces with confidence before anyone else puts a price on them.