Hallmark Chart: Gold, Silver & Platinum Jewelry Marks

Gold: karat, number, purity

Karat	Number mark	Gold content
24K	999	99.9%
22K	916	91.6%
18K	750	75%
14K	585	58.3%
10K	417	41.7%
9K	375	37.5%

The letters that cancel the number

GP, GEP, HGE, RGP: plated, a microns-thin gold skin. GF, often “1/20 14K GF”: gold-filled, thicker but still a skin. Vermeil: gold over sterling silver. When these letters follow a number, go by the letters. More on GF, GP, and HGE.

Platinum

PLAT, PT, 950, 900, 850, read beside PT or PLAT. 10% IRID PLAT means 90 percent platinum and 10 percent iridium. A 900 beside PT or PLAT is platinum, not silver.

Silver: the real ones and the impostors

Real silver	Purity	Common origin
999	99.9%	Fine or investment silver
958 / 950	95%+	Britannia (UK); French first standard
925 / STERLING	92.5%	The global benchmark
900	90%	Coin silver in the U.S.; also an Egyptian standard
835 / 830 / 800	80 to 83.5%	German, Dutch, Scandinavian, and Italian standards

No silver despite the name: German Silver, Nickel Silver, and Alpacca (a copper-nickel-zinc alloy), plus EPNS, EP, SP, and A1, which are plating grades. Does 925 prove silver?

Picture marks worth memorizing

Mark	Country	Meaning
Lion passant (walking lion)	Britain	Sterling silver, assay-tested
Leopard’s head / anchor / rose / castle	Britain	Assay office: London / Birmingham / Sheffield / Edinburgh
Date letter (one letter in a shield)	Britain	The year, read with the letter’s typeface and shield (alphabets repeat)
Eagle’s head	France	18K gold, state-tested, since 1838
Horse’s head	France	18K gold, small pieces tested outside Paris, 1838 to 1919
Owl	France	Imported gold, tested at customs
Minerva head (numeral 1 or 2)	France	Silver: 950 or 800
Lozenge-shaped punch	France	Maker’s mark
Crescent moon + crown	Germany	Official mark, 1888 to 1933
Star + number + province code	Italy	Registered maker; required since 1968
Kokoshnik (woman’s head); 56 / 84	Imperial Russia	Assay mark; zolotnik purity (56 is about 14K)
583	Soviet Union	The USSR’s 14K standard
Eagle in a cartouche	Mexico	Silver, 1948 to 1979 (eagle 3 = Taxco); letter codes after 1979
Helvetia head / squirrel	Switzerland	Watch cases: 18K / 14K, under Swiss precious-metals control since 1882

Which marks to trust most

A picture mark means a government office tested the metal. An American number mark such as 14K is the maker’s own claim, which is why U.S. law has required a maker’s mark beside it since 1961. Either way, check the piece as well as the stamp.

Four questions to check any stamp

Is there a maker’s mark beside it (on modern pieces)?
Does the stamp’s wear match the rest of the piece?
Does the price make sense for the metal the stamp claims?
Do the wear points show one metal, not two?

For anything not on this page, three free lookup libraries go deeper: the 925-1000.com marks encyclopedia, the UK assay offices’ date-letter tables, and Lang’s maker’s-mark database. The book’s chapters five and seven teach these marks with their sources.