Someone sets a chain on the counter, it's stamped 14K, it tests a hair under 14K, and their face drops. They assume one of two things: the chain is fake, or the shop is shaving the number. Most of the time it's neither. A karat stamp is a promise with a margin written into federal law, and a chain is not one piece of metal. Here is what's actually going on.
14K isn't a round number to begin with
Karat is parts out of 24. Fourteen parts of pure gold out of 24 is 58.33%. The European stamp for the same alloy is 585, which is 58.5% — slightly richer than the fraction it stands for. Same story at 10K: ten parts out of 24 is 41.67%, and the stamp rounds it up to 417. So before anything else happens, "14K" and "585" already describe two slightly different targets. If you want the full list of stamps, our guide to gold hallmark stamps has them.
The law allows a piece to come in under its stamp
In the United States, the National Gold and Silver Stamping Act — with the FTC's Jewelry Guides alongside it — lets a gold article run slightly below the karat it's marked with and still be legally marked:
- No solder: up to 3 parts per thousand under the mark.
- With solder: up to 7 parts per thousand under the mark, and the whole article is measured, solder included.
Seven parts per thousand sounds like nothing. On a soldered 14K chain it means the chain as a whole can legally come in around 57.6% instead of 58.3%. It is still 14K by law.
The only stamp that promises no shortfall at all is "plumb" — a piece marked plumb is supposed to meet its karat with no negative tolerance. You rarely see it.
Older gold played by looser rules
For most of the twentieth century the allowance was far wider: the original 1906 law let a piece come in up to half a karat under its stamp, and the tighter parts-per-thousand limits came with amendments that took effect in the early 1980s. Half a karat on a 14K ring means a piece that was perfectly legal in its day can be closer to 13.5K. When an estate ring from a grandparent's jewelry box reads a little low, that's usually the reason. Nobody cheated anybody. The rules were just different.
A chain is dozens of little joints
Solder is the metal used to close a link or attach a clasp, and it has to melt at a lower temperature than the gold around it. Lowering the melting point means changing the alloy, so solder usually carries less gold than the piece it joins. A Cuban link has a soldered joint in every link. A rope chain is built from small soldered sections. The more joints, the more of the chain's weight is solder, and the more the average drifts toward the bottom of that 7-per-thousand band.
Then there's the clasp. A spring-ring clasp has a small steel spring inside it, because gold is too soft to hold spring tension. Lobster clasps have springs too. None of that is gold, and a buyer has to account for it, which is why our testing process separates clasps and other non-gold parts before the gold is priced. On a heavy chain it's a rounding error. On a thin 16-inch chain, the clasp is a real share of what the scale says.
Where it stops being legal
The tolerance is a few thousandths. It is not a karat. A chain stamped 14K that reads like 12K, or a "10K" piece that reads like 8K, is not a solder story — it's underkarated, and that's a mismarked piece no matter who made it.
There's a second rule people don't know about: US law expects anyone who applies a karat stamp to put a registered trademark next to it. That's why good American pieces carry a maker's mark beside the 14K. A crisp karat stamp with nothing beside it isn't proof of anything by itself — lots of imported and older pieces lack one — but it's worth noticing, especially on a chain being sold to you at a price that seems too good. Our piece on spotting a fake gold chain covers what fakes look like.
What this means when you sell
A buyer pays on the gold that's actually there. The math is weight times purity times the day's gold price — nothing more complicated than that — so the purity figure matters. If your piece reads slightly under its stamp:
- Don't assume you're being cheated. A reading just under the mark on a soldered piece is exactly what the law allows for.
- Do ask to see the test. Any honest buyer will show you the reading and the scale. We test on camera for that reason.
- Do ask about the clasp. If it's being deducted, you should know by how much weight.
- Weigh the difference in dollars, not pride. On a few grams, a few thousandths of purity comes to very little money. Use our gold calculator with both numbers and see.
The weight side matters more than people expect, too. Width scales faster than you think (chain width vs. gold weight), and stones and settings add grams that aren't gold (why a heavier ring can be worth less).
And when you buy
Our case has more than 170 active listings in 14K and more than 170 in 10K right now, and each one is listed with its karat and its gram weight. That's the question to ask any seller, anywhere: not "is it real?" but "what did it test at, and what does it weigh?" A seller who can answer both is selling you gold. A seller who can only point at the stamp is selling you a stamp.
Browse gold chains or Cuban links, and if you want the karat comparison itself, start with 10K vs. 14K vs. 18K.
The advice that doesn't help us
If you bought a piece new, from a jeweler, and it reads well under its stamp — not a few thousandths, but a real gap — the conversation you want is with the seller who sold it to you, while you still have the receipt. Not with us. Selling it for melt settles nothing about how it was marked.
And don't have a worn stamp re-struck or "cleaned up" before you sell. A faint original stamp tells a buyer more than a fresh one.
Bring any piece to DD Pawn Loans, 2751 W Atlantic Blvd #101, Pompano Beach and we'll test and weigh it in front of you, free, whether you sell or not. Mon–Thu 10am–7pm, Fri 9am–8pm, Sat 10am–7pm, closed Sunday. Call or text (561) 774-9292. Selling locally? See selling gold in Pompano Beach. Collateral loans are available too, with no credit check — details on our collateral loans page.