GF (gold filled)

How to read it

The FTC’s jewelry guides reserve gold filled, like rolled gold plate and gold overlay, for a layer of gold alloy of at least 10 karat applied by a mechanical process (soldering, brazing, welding or other mechanical means), with the karat of that layer marked first. Gold filled is the heaviest of these: the plating has to make up at least 1/20th of the weight of the metal in the whole piece, which is what a mark like 1/20 12K GF states. The Stamping Act names gold filled among the plated goods its rules cover.

Also searched as: 1/20 12K GF, G.F., GF, gold filled.

What’s the difference between gold filled and gold plated?

How the gold is applied and how much of it there is. Under the FTC’s guides, gold filled is a mechanically applied layer of at least 1/20th of the metal’s weight; gold plate made by electroplating needs a layer only 0.175 microns thick. Rolled gold plate is the same mechanical process as gold filled, with a thinner layer.

Reading 1/20 12K GF

Each part of the mark answers a different question. 1/20 is the share of the weight of all the metal in the article that the gold layer accounts for. 12K is the karat of that layer, not of the whole piece. GF names the process. The FTC’s consumer guide adds that where the layer is less than 1/20 of the weight, the marking should state the fraction, as in 1/40 14K gold overlay; gold filled on its own implies at least 1/20.

A gold mark on a filled piece

The Stamping Act does not let a plated or filled article carry a mark usually used for the fineness of gold unless it is accompanied by words plainly saying the article is rolled gold plate, gold plate, gold electroplate or gold filled. The same section bars the words sterling and coin from such goods altogether. The FTC’s guides also cover a layered construction: gold plating covered with a base metal such as nickel and then a thin wash of gold should be disclosed as such, and not simply called gold filled.

Parts the mark does not cover

The FTC’s guides list parts that are not considered in any assay of a gold filled, gold overlay or rolled gold plate product, other than watchcases, among them joints, catches, screws, pin stems, springs and bracelet and necklace snap tongues. A clasp spring on a gold filled chain is outside the claim.

Gold filled in Britain

There is no British hallmark for it. The UK assay offices’ guidance notes say gold-plated base metal cannot be hallmarked, and that includes bonded gold and rolled gold on base metal. The Hallmarking Act allows the word gold on an unhallmarked article only when it is qualified by the word plated or rolled, and in writing that word has to be in lettering at least as large as the rest of the description. Business Companion, the Chartered Trading Standards Institute’s guide, says the description rolled gold is permitted if it is true. The guidance notes add that a bonded gold layer must be at least 375 parts per thousand and of a fineness recognised in the UK, so bonded gold of 10k can only be described there as 9 carat.

Who the mark comes from

In the US the Stamping Act’s trademark rule applies to any quality mark indicating that an article is made in whole or in part of gold, so a GF quality mark comes with the name or trademark of whoever applied it.

Optical frames, pens and flatware

The FTC’s guides cover optical frames, pens and pencils, flatware and hollowware as well as jewelry. They give a separate list of parts left out of the assay of gold filled, gold overlay and rolled gold plate optical products.