Flip over a ring, a bracelet, or a pendant, and somewhere on the metal you’ll usually find a tiny stamp. Most people glance past it. Jewelers and buyers read it like a paragraph, since it packs in details that would otherwise take an expert eye and a scale to figure out.
That small mark carries more information than almost anything else on the piece, and learning to read it changes how you shop, sell, and value what’s already sitting in your jewelry box.
The Tiny Stamp With a Big Job
So what is a jewelry hallmark, exactly? It’s a small stamped mark on a precious metal item that certifies its purity, and sometimes its maker or country of origin. Think of it as a built-in ID card, permanently pressed into the metal itself rather than printed on a tag that can fall off or get lost. Unlike a receipt or a certificate of authenticity, a hallmark stays with the piece for as long as it exists.
Hallmarks usually show up in discreet spots: inside a ring band, near the clasp of a necklace, on the post of an earring, or the underside of a bracelet. A jeweler can confirm exactly what a hallmark means in a matter of minutes, since some marks are faint, worn, or unfamiliar to anyone outside the trade.
What Is a Gold Number, Exactly?
Gold hallmarks show up in one of two formats. Karats (10K, 14K, 18K) are the version most people recognize in the United States. But gold numbers, also called millesimal fineness, express the same purity as parts per thousand instead.
Here’s how the two systems line up:
- 24K = 999 — 99.9% pure gold
- 22K = 916 — 91.6% pure gold
- 18K = 750 — 75% pure gold
- 14K = 585 — 58.3% pure gold
- 10K = 417 — 41.7% pure gold
A gold number isn’t a different metal or a lower standard. It’s simply the same purity information written in a format that’s more common outside the U.S., particularly across Europe and parts of Asia. Once you know the pairing, converting between the two systems becomes second nature.
What Does 585 Mean on Jewelry?
The number 585 stamped inside a ring or on a clasp means the piece is 14K gold, or 58.3% pure gold by weight. This is one of the most common purities used in fine jewelry, since it strikes a balance between gold content and everyday durability.
If you see 585 alongside other symbols, those additional marks likely point to the maker or the country where the piece was assayed. On its own, though, 585 confirms one thing clearly: the piece is genuine gold, not plated, and it’s one of the most durable everyday karats available.
What Does 750 Mean on Jewelry?
A 750 stamp means the piece is 18K gold, or 75% pure gold by weight. This purity is often considered the standard for fine, luxury jewelry, since it offers a richer color and higher intrinsic value than 14K while still holding up well to daily wear.
Because 18K and 750 refer to the exact same purity, you’ll sometimes see jewelry stamped with either mark depending on where it was made. European and Asian pieces lean toward the numerical format, while American jewelry tends to favor the karat label. Neither format is more accurate than the other; they’re simply two ways of saying the same thing.
Beyond Gold: Other Common Stamps
Gold isn’t the only metal with its own numbering system. A few other marks are worth recognizing on sight:
| Stamp | Metal | Purity |
| 999 | Fine gold or silver | 99.9% pure |
| 925 | Sterling silver | 92.5% pure |
| 950 | Platinum or palladium | 95% pure |
| 900 | Platinum | 90% pure |
Seeing one of these numbers alongside a small symbol or set of initials usually means there’s a maker’s mark or assay office mark included as well, adding another layer of detail about who made the piece and where it was tested. Older or antique pieces sometimes carry more elaborate marks, including symbols tied to a specific city or era, though modern jewelry has largely simplified down to just the purity number.
A Word on Maker’s Marks
Purity numbers aren’t the only story a hallmark can tell. Many pieces also carry a maker’s mark, a small stamp of initials, a symbol, or a full brand name identifying who actually produced the item. On a piece from a recognized jeweler, this mark can add significant value on top of the metal itself, since collectors often pay a premium for a known name alongside verified purity.
Not every piece carries one, especially mass-produced or older jewelry where the maker’s identity was never a selling point. When a maker’s mark is present, though, it’s worth researching alongside the purity stamp rather than treating it as a footnote.
Spotting a Fake Before You Buy or Sell
Not every stamp is trustworthy. Counterfeit hallmarks tend to give themselves away in a few ways, especially once you know what genuine stamping looks like:
- Shallow, uneven, or blurry stamping compared to the sharp edges of a genuine mark
- A purity number with no accompanying maker’s mark or assay symbol where one would normally be expected
- A mismatch between the stated purity and the item’s weight or magnetic properties
None of these checks require special equipment on their own, but they’re rarely conclusive without a second opinion. Bringing a piece in to be looked over by someone who handles hallmarks daily settles the question far faster than guessing from a photo or an online chart, and it’s the only way to catch a well-made fake that passes a casual glance.
What a Hallmark Means for What You’ll Get Paid
Once you know how to read a hallmark, the value conversation gets a lot simpler. A confirmed 14K, 18K, or sterling silver stamp tells a buyer exactly what they’re working with before a single scale comes into the picture, cutting out a lot of back-and-forth over what a piece might or might not be made of.
Items without a clear stamp, or with one that looks questionable, usually need a purity test before an accurate offer can be made. Getting a free, no-pressure quote on your gold starts with exactly this step, confirming what the hallmark says and matching it against the current market price before any number gets discussed.
The Stamp That Tells the Whole Story
A jewelry hallmark is a small detail with an outsized job. It confirms purity, hints at origin, and sometimes even points to the maker behind the piece. Whether you’re staring at a 585, a 750, or an unfamiliar symbol you’ve never noticed before, that stamp is the fastest way to understand exactly what you’re holding.
Next time you pick up a piece of gold or silver jewelry, take a second look at what’s stamped inside. It’s a small habit that pays off the moment you actually need the answer, whether that’s out of curiosity or because you’re finally ready to find out what it’s worth.
