Gallery
What the stamp inside means
Every mark you are likely to find, sorted by what it actually claims — solid metal, a plated layer, or nothing precious at all.
Try 925, 585, GF, PLAT, or the words — sterling, nickel silver, gold filled.
26 marks in the reference below.
A stamp is a claim, not a certificate
In the UK, Ireland and much of Europe, an assay office physically tested the metal and struck its own mark to back the claim up. In the US and most of the rest of the world, the maker struck the number themselves and nobody checked. Both look identical to somebody holding a ring. The difference is worth knowing before you rely on one.
Solid precious metal
The piece is an alloy of the metal named, all the way through. These marks state how much of it is the pure metal, in parts per thousand.
| Mark | Also stamped | What it means |
|---|---|---|
| 375 | 9K, 9CT | 9 carat gold — 37.5% gold, the rest other metals.Legal to sell as gold in the UK and Ireland but not in the US, where the floor is 10K. Hard-wearing, and noticeably paler than 18K.Found in: UK, Ireland |
| 417 | 10K, 10KT | 10 carat gold — 41.7% gold.The lowest purity that US law allows to be described as gold.Found in: US, Canada |
| 585 | 583, 14K, 14KT, 14KP | 14 carat gold — around 58.5% gold.The most common fine-jewellery gold in the US. 14K works out at 583.3 exactly, so you will see both 583 and 585 stamped; the P in 14KP means "plumb", i.e. exactly 14K rather than a hair under. It is not plated.Found in: US, and worldwide |
| 750 | 18K, 18KT, 18CT | 18 carat gold — 75% gold.The European fine-jewellery standard. Warmer in colour than 14K and softer.Found in: Europe, and worldwide |
| 916 | 917, 22K, 22KT | 22 carat gold — 91.6% gold.The South Asian standard, and the usual purity for gold bought as a store of value rather than as a design.Found in: India, Pakistan, Bangladesh, the Gulf |
| 875 | 21K | 21 carat gold — 87.5% gold.Found in: The Gulf, Egypt, North Africa |
| 999 | 24K, 9999 | Effectively pure gold.Too soft to hold a stone or survive daily wear, so on jewellery it usually means a bangle or a coin mount rather than a ring. |
| 925 | STER, STG, STERLING | Sterling silver — 92.5% silver, usually with copper.By far the most common silver mark in the world. All four of these stamps mean exactly the same thing. |
| 800 | — | 80% silver.Common on continental European cutlery, cigarette cases and older tableware.Found in: Germany, Italy, Austria |
| 900 | COIN | Coin silver — 90% silver.The old US coinage standard; on flatware it usually means pre-1870 American. |
| 958 | BRITANNIA | Britannia silver — 95.8% silver.Found in: UK |
| PLAT | PT950, 950 PLAT, PLATINUM | Platinum, normally 95% pure.Much denser than gold — a platinum ring feels obviously heavy for its size, and that heft is the quickest informal check there is. |
| PD950 | PALL, PD500 | Palladium.Looks like platinum and weighs about half as much. Widely used for white wedding bands in the 2000s. |
Plated, filled and rolled
A thin layer of precious metal over a base-metal core. The layer is real gold or silver, and there is not enough of it to be worth recovering — refiners will not normally buy these at all.
| Mark | Also stamped | What it means |
|---|---|---|
| GP | GEP, GOLD PLATED, 18KGP, 14KGP | Gold plated — a microscopically thin layer of gold over another metal.A number in front of GP describes only the plating, not the item. "18KGP" is not 18 carat gold; it is 18 carat gold plating over something else, and the layer is typically under half a micron. |
| GF | 1/20 12K GF, 1/10 14K GF, GOLD FILLED | Gold filled — a bonded layer of gold that is a stated fraction of the total weight.Far thicker than plating, and the fraction is on the stamp: "1/20 12K GF" means one twentieth of the weight is 12K gold. It wears for decades, but the gold content is still too small for a scrap buyer to be interested. |
| RGP | ROLLED GOLD, RG | Rolled gold plate — like gold filled, with a thinner layer. |
| HGE | HEAVY GOLD ELECTROPLATE | Heavy gold electroplate — plating, despite the word heavy.Applied by electricity rather than bonded under heat and pressure. Thinner than gold filled. |
| VERMEIL | — | Gold over sterling silver.The exception worth knowing in this group: the core is real silver, so a vermeil piece does have recoverable metal value — as silver. |
No precious metal at all
Marks that look like precious-metal marks and are not. Several of these contain the word "silver" and none of them contain any silver.
| Mark | Also stamped | What it means |
|---|---|---|
| NS | NICKEL SILVER, GERMAN SILVER, ALPACA, ALPACCA | Contains no silver whatsoever.A copper, nickel and zinc alloy that happens to be silver-coloured. The name is a description of the colour, and it has misled people for two hundred years. |
| EPNS | EP, A1, SILVER ON COPPER | Electroplated nickel silver — a silver skin over the alloy above.Very common on Victorian and Edwardian tableware. The plate is too thin to recover. |
| SS | — | Ambiguous, and worth resolving before you assume.On jewellery SS most often means stainless steel. Some makers have used it for sterling silver. A magnet settles it in a second: stainless is usually magnetic and silver never is. |
| BASE | BM, STEEL, BRASS | Base metal, stated plainly. |
Assay and maker marks
The rest of a hallmark: who made it, who tested it, and when. Only some countries operate a system like this.
| Mark | Also stamped | What it means |
|---|---|---|
| UK hallmark | — | Three compulsory marks struck by an assay office that physically tested the metal.A sponsor mark saying who submitted it, a millesimal fineness number in a shaped shield, and the assay office town mark — a leopard’s head for London, an anchor for Birmingham, a rose for Sheffield, a castle for Edinburgh. This is the strongest assurance in the world that a stamp is true, because the state tested it rather than the seller.Found in: UK, Ireland |
| Date letter | — | A letter in a shaped shield giving the year the piece was assayed.Optional in the UK since 1999 but struck for centuries before that. The letter, its typeface and the shape around it together identify a single year, which is how British silver can be dated exactly.Found in: UK |
| Eagle's head | Crab, Boar’s head | French assay marks.An eagle’s head is 18K gold, a crab is 950 platinum, and a boar’s head or a crab denotes silver depending on the era.Found in: France |
| Maker’s mark | — | Initials or a symbol in a shaped surround, identifying who made or sponsored it.On its own it says nothing about purity. Next to a recognised maker it can be worth many times the metal — which is the strongest reason to identify a mark before selling anything for scrap. |
Checks you can do without damaging anything
None of these prove a piece is genuine. Each one can prove it is not, which is more useful than it sounds and is all that a test at a kitchen table can honestly do.
A magnet
Gold, silver, platinum and palladium are not magnetic. A piece that jumps to a magnet has a base-metal core or a steel component. A piece that ignores the magnet has not proved anything — plenty of base metals are non-magnetic too — so this test can rule out, never rule in.
Weight for size
Density is hard to fake. Platinum is about 40% heavier than 18K gold for the same size, and both are far heavier than the plated base metals. A ring that looks substantial and feels light is telling you something.
Wear at the edges
Plating wears through first where the piece rubs — the underside of a ring shank, the edge of a clasp, the high points of a chain. A different colour showing through at those points is the plating gone.
A green line on the skin
Solid precious metal does not do this. The reaction is between skin and the copper in a base-metal core, which means the plating has worn through somewhere.
The stamp itself
Look at it under magnification. Genuine marks are struck cleanly into the metal or laser-cut precisely. A mark that is blurred, uneven or sitting on top of the surface rather than in it is worth questioning.
Deliberately absent: acid testing. It works, and it needs reagents, ventilation and a willingness to mark the piece — none of which belong in a set of instructions handed to a stranger about their grandmother’s ring. Any jeweller will test it in front of you, usually for nothing.
Common questions
What does 925 mean on a ring?
It means sterling silver: 92.5% silver, with the remainder usually copper. STER, STG and the word STERLING all mean the same thing. It says nothing about the quality of the workmanship or the value of any stones — only what the metal is.
Is 18KGP the same as 18K gold?
No, and the difference is enormous. The GP stands for gold plated, and the number in front describes the plating rather than the item — 18KGP is a layer of 18 carat gold, typically well under a micron thick, over some other metal. A refiner will not buy it, because there is not enough gold present to be worth recovering.
What does the P in 14KP mean?
Plumb — as in exactly, from the same root as a plumb line. 14KP is a guarantee that the metal is a full 14 karats rather than a fraction under, which used to be common. It has nothing to do with plating, and it is a slightly stronger claim than a plain 14K stamp, not a weaker one.
My piece has no stamp at all. Is it fake?
Not necessarily. Stamping has never been universal — a great deal of genuine older and handmade jewellery carries no mark, and marks also wear away on the inside of a much-worn ring or get polished off during a resize. An unmarked piece simply has to be tested rather than read, which any jeweller can do while you wait.
Does nickel silver contain silver?
None whatsoever. Nickel silver — also sold as German silver, alpacca or NS — is copper, nickel and zinc. The name describes the colour and has been misleading people for about two hundred years. The same is true of EPNS, which is a thin silver plating over that alloy.