Gold Hallmarks and Stamps: What the Numbers Mean Before You Sell
The tiny numbers stamped inside a ring or on a chain clasp tell you what a piece claims to be. That claim is your starting point before you sell, not the final word. Here is how to read the marks, what each one means in plain terms, and why a stamp still has to survive a test and a weigh-in before anyone can quote you a fair figure.
Most gold items carry a small mark somewhere discreet: the inside of a ring band, the flat of a clasp, the back of a pendant, or a link near the catch. Grab a bright light and a loupe or your phone camera zoom. The mark is often worn or shallow, so tilt the piece until the numbers catch the light.
Two systems dominate. One uses a three-digit number that states purity as parts per thousand. The other uses the karat scale you already know, written as a number followed by K or KT. Both point to the same thing: how much of the metal is actually gold versus alloy added for strength and color.
What the Numbers on Your Gold Actually Mean
The three-digit stamps are read as a fraction of 1,000. A 585 mark means 585 parts gold per thousand, which is 58.5 percent pure. That is the European way of writing 14 karat. A 750 stamp means 75 percent pure, the same as 18 karat. 916 means 91.6 percent, which lines up with 22 karat and is common on jewelry from India and the Middle East. You will also see 375 for 9 karat, 417 for 10 karat, and 999 for near-pure bullion.
The karat stamps map directly. 10K is 41.7 percent gold, 14K is 58.5 percent, 18K is 75 percent, 22K is 91.6 percent, and 24K is as pure as it gets. Higher karat means more gold in the metal, softer feel, and a deeper yellow tone. Lower karat wears harder and holds up to daily knocks, which is why so many rings land at 10K or 14K.
Alongside the purity mark you may find a maker's mark, usually a set of initials or a small symbol registered to the manufacturer. Next to that, some items carry a country or assay hallmark, a stamped guarantee from an official testing office. British pieces, for example, often show a small set of symbols for the assay office, the metal, and the year. These extra marks help confirm the piece is what it claims, but they do not change the value on their own.
Watch for letter codes that signal the metal is not solid gold. GP means gold plated. GF means gold filled, a thicker layer bonded to a base metal. GE or HGE means gold electroplate. RGP means rolled gold plate. A mark like 1/20 12K GF tells you a thin fraction of 12 karat gold covers a base core. These items have real gold on the surface, but the payout reflects a coating, not solid content.
Why the Stamp Alone Does Not Set Your Payout
A stamp is a claim made by whoever produced the piece. Most claims are honest, but a mark can be wrong, faked, or applied to plated goods to imply more than is there. That is why any straight buyer tests the metal instead of trusting the number at face value. A quick acid test on an inconspicuous spot, or an electronic conductivity test, confirms the karat. Higher-value or larger lots often get an X-ray fluorescence read, which shows the exact alloy makeup without a scratch.
There are simple tells that a stamped piece may be plated. Green or dark discoloration at worn edges points to base metal showing through. A clasp or a small tag that carries the stamp while the rest of the piece is unmarked can mean a plated body with a solid tag. A magnet pull is another quick check: gold is not magnetic, so any tug suggests a steel or base-metal core under a thin gold skin. None of these are proof by themselves, but they tell a buyer to look closer before quoting.
Once purity is confirmed, weight does the rest. Gold is priced by the gram, and only the gold content counts. A buyer weighs the item on a calibrated scale, subtracts anything that is not gold such as stones, clasps made of other metal, or spring bars, and applies the current market rate for that karat. This is why two rings that both read 14K can be worth very different amounts: one is a heavy signet, the other a thin band, and the gram count separates them.
A few practical steps put you ahead before you sell. Sort your pieces by stamp so 10K, 14K, and 18K are grouped, since mixed karats get weighed and paid separately. Set aside anything marked GP, GF, or HGE so you are not surprised when it prices low. Note that stones and non-gold parts get deducted, so a chunky gemstone ring pays on less gold than its total weight suggests. And bring the unmarked pieces too; plenty of older or handmade gold was never stamped, and a proper test can still confirm it.
Read the marks, but treat them as the opening line of the conversation. The stamp tells you what to expect. The test confirms it, and the scale sets the number. When you understand all three, you walk in knowing roughly what your gold should bring, and you can tell a fair offer from a low one.