Gold Hallmarks: How to Read Every Stamp on Your Jewelry

Where the Marks Hide

Stamps go where they won't spoil the look, which means you need to know the hiding spots:

• Chains and bracelets: on the clasp itself, on the small flat tag (jump-ring tab) next to the clasp, or on the last link.
• Rings: inside the band (the shank), sometimes worn faint by decades of fingers.
• Earrings: on the post, or on the back of the setting — the smallest and hardest stamps to read.
• Pendants and charms: on the bail (the loop the chain runs through) or the flat back.
• Watches: inside the case back, which may require opening; case and bracelet can be different metals.
• Pins and brooches: on the catch mechanism or the back plate.

Use a 10x loupe, or do what works just as well: photograph the spot with your phone and zoom in. Angle light across the surface rather than straight on — a raking light throws shadows into the engraving and makes faint marks legible. Clean grime out of the area with a soft cloth first; half of "unmarked" jewelry is just unwashed jewelry.

One piece can carry several stamps in a row: a purity mark, a maker's mark, sometimes a country or assay mark. Read all of them before concluding anything — the most informative stamp is often the second one.

Karat Stamps vs Fineness Numbers

American jewelry talks in karats: 10K, 14K, 18K, sometimes with variations like 14KT or 585 alongside. European and most international jewelry talks in millesimal fineness: a three-digit number giving parts of gold per thousand. They're the same information in two dialects — 14K and 585 both mean 58.33% gold; 18K and 750 both mean 75%.

A few wrinkles worth knowing. 14KP means 14 karat plumb — "plumb" as in exact, a 1970s-era American assurance that the piece assays at a full 14K and not the slightly-under that older tolerances allowed. It does not mean plated; this one trips people constantly. A karat mark with a letter prefix like "18K HGE" is the opposite situation — the karat number describes only the microscopic plating, and the HGE is the confession. Always read the whole stamp, not just the number that catches your eye.

Numbers you'll actually encounter: 999 (24K), 916 or 917 (22K), 875 (21K), 750 (18K), 585 or 583 (14K), 417 (10K), 375 (9K). The full percentage-and-value breakdown for each lives in the gold purity chart. Anything outside that family — 800, 900, 925 — is almost certainly a silver fineness mark, no matter how golden the piece looks.

The Decoder Table

Every common stamp, sorted from best news to worst:

The pattern to internalize: a bare karat number or fineness number is good news; that same number followed by letters (GF, GP, HGE, RGP) is a disclosure that the gold is a coating. And a maker's mark alone — initials in a box, a brand logo — tells you who made the piece but nothing about what it's made of; look for the purity stamp beside it.

The Plated Codes, With the Math Done

Gold-filled deserves its own arithmetic, because the stamp literally is the recipe. 1/20 12K GF decodes as: the gold layer constitutes 1/20th of the item's total weight, and that layer is 12K (50% pure gold). So in a 10-gram gold-filled bangle: 10 g ÷ 20 = 0.5 g of 12K alloy, and 0.5 g × 50% = 0.25 grams of pure gold — 2.5% of the piece by weight. At an assumed $4,400 per troy ounce ($141.46/g pure), that's about $35 of gold spread over the whole bangle. A solid 14K bangle of identical 10 g weight carries about $825 of gold. Same look on the wrist; twenty-three times the metal value.

In practice even that $35 is mostly theoretical: separating a fraction of a gram of gold from brass costs refiners real work, so gold-filled only gets bought in bulk lots at modest per-pound prices. Single gold-filled pieces are worth more as wearable vintage jewelry than as scrap — sell the look, not the metal.

Plated marks go downhill from there. Standard electroplate (GP, GEP) is measured in fractions of a micron; HGE — "heavy" gold electroplate — sounds reassuring and isn't, since the industry's idea of heavy is a coating still thinner than a soap bubble. RGP (rolled gold plate) uses the gold-filled process with less gold. Vermeil is the aristocrat of the category — real sterling silver under a thicker-than-usual gold plate — and prices as silver plus craftsmanship. None of them have meaningful gold melt value, which is the polite, persistent message of those little letters.

International Marks: A Field Guide

Inherited and travel-bought jewelry brings foreign gold hallmarks to American kitchen tables daily. The quick translations:

United Kingdom: the world's oldest consumer-protection scheme, running for over 700 years. A full UK hallmark is a row of tiny pictorial punches: a maker's (sponsor's) mark in a shield, a millesimal fineness number (375, 585, 750), and an assay office symbol — a leopard's head for London, an anchor for Birmingham, a rose for Sheffield, a castle for Edinburgh. Older pieces add a date letter that specialists use to year a piece precisely. A genuine UK hallmark is strong evidence; the metal was independently tested at an assay office by law before sale.

Continental Europe: typically fineness numbers (750 is everywhere in Italy and France), often with national symbols — France's eagle head for 18K is the famous one. Italian pieces frequently add a star-and-number maker code identifying the workshop.

Middle East and South Asia: high-karat fineness numbers — 875 (21K) across the Gulf, 916 with the BIS triangle in India, 999 on Chinese pieces sold as "chuk kam" (pure gold).

Russia and Eastern Europe: Soviet-era pieces often carry 583 with a star punch; modern Russian gold uses 585 with a woman's-head profile (the kokoshnik mark).

The unifying rule: a three-digit number from the standard family means the same purity everywhere on Earth. The decorations around it tell you where and when; the number tells you what it's worth.

No Mark? Worn Mark? Here's the Playbook

An unmarked piece is not a fake piece — context matters enormously. The United States only required purity marking alongside a maker's trademark relatively recently in jewelry history: the National Gold and Silver Stamping Act of 1906 regulated the accuracy of marks but didn't force anyone to stamp at all, so plenty of genuine American gold made before the mid-20th century — and essentially all of it before 1906 — carries no purity mark whatsoever. Handmade pieces, resized rings (resizing can cut the stamp out of the band), and heavily polished heirlooms round out the innocent explanations. Antique unmarked gold is, if anything, a category where pleasant surprises cluster.

The playbook when the shank is blank or the stamp is too worn to read:

1. Photograph and zoom anyway — marks that look gone to the naked eye often survive in a raking-light photo.
2. Check every component: clasp, tag, bail, post. Multi-part pieces get stamped in one place only.
3. Run the free physical tests — magnet, density — and then an acid test at the likely karat, per our walkthrough of how to test gold at home.
4. For anything promising or sentimental, get a free XRF scan at a coin or bullion dealer; it reads exact composition in seconds without touching the surface.

Buyers price unmarked, untested gold pessimistically — assume-the-worst is their default. Showing up with test results, or simply knowing them yourself, removes that discount from the conversation. This matters double for estates, where unmarked pieces are most common; our guide to selling inherited gold jewelry covers the valuation order of operations.

Fake Stamps on Fake Gold

Here is the uncomfortable truth that keeps this entire topic honest: a stamp is a claim, and claims can be counterfeited with a $30 punch set. Fake chains stamped 18K and 750 circulate in volume — tourist markets, online marketplaces, and the classic street hustle of the "stranded traveler" selling a stamped gold rope chain at a too-good price. The stamp is part of the costume. Counterfeiters know exactly how much trust those little characters carry, which is why they apply them generously.

Red flags that a mark is lying: purity stamps on pieces that feel too light for their size (gold is dramatically denser than brass), stamps that are unusually large, crooked, or freshly sharp on an allegedly old piece, fineness numbers that don't exist in the standard family (a stamp reading 770 or 460 was punched by someone improvising), and sellers whose price implies they don't believe their own stamp. The Federal Trade Commission's jewelry guides make misrepresenting purity illegal in US commerce — the FTC's advice on selling gold jewelry is equally useful in reverse, as a checklist of what honest marking looks like — but laws govern sellers who expect to be findable tomorrow. A flea-market vendor with a folding table operates under different incentives.

The defense never changes: the stamp tells you what to test for, and the test tells you whether the stamp told the truth. Magnet, density, acid, XRF — in that order of effort. Gold hallmarks read with a skeptic's eye are a superpower; read with pure faith, they're the most efficient scam-delivery mechanism ever pressed into metal.

Reading a Real Piece, End to End

Let's run the whole method on a typical estate-box find: a yellow chain with a tiny tag by the clasp.

Under the phone camera at full zoom, the tag shows two punches: 585 and a boxed "M&Co". Translation: millesimal fineness 585 — solid 14K, 58.33% gold — plus a maker's mark identifying the manufacturer. No GF, no GP, no HGE anywhere on tag, clasp, or end links. The magnet ignores it (the clasp pulls faintly — steel spring, normal). The pocket scale says 31.0 g.

Now the money math, assuming spot gold at $4,400 per troy ounce, i.e., $141.46 per gram pure:

1. Pure gold content: 31.0 g × 58.33% = 18.08 g
2. Melt value: 18.08 g × $141.46 = $2,557.60
3. Realistic offers against that melt: a local coin or bullion dealer at 65–85% pays $1,662–$2,174; a jewelry store at 50–75% pays $1,279–$1,918; a pawn shop at 40–60% pays $1,023–$1,535.

Ten minutes of reading and weighing turned "grandma's chain, probably gold?" into a defensible number and a ranked list of places to sell it. Had the tag read 1/20 14K GF instead, the same ten minutes would have saved a wasted trip and reframed the chain as vintage costume jewelry. Either way the marks did their job — they're the cheapest expertise in the gold world, sitting in plain sight on the back of the clasp, waiting for someone to finally look.

Frequently Asked Questions