Gold Hallmark Stamps: What 585, 750, and 417 Actually Mean

That tiny number stamped on the inside of your ring or the clasp of your chain tells you exactly how much gold your piece contains. Once you know how to read it, you can instantly calculate what any piece is worth. Here’s the complete guide.

What Is a Hallmark?

A hallmark is an official mark stamped onto precious metal items to certify their purity. In the US, the FTC requires that any piece sold as gold be accurately marked with its karat or fineness. You’ll typically find the stamp on the inner band of rings, the jump ring or clasp of necklaces, and the post or clasp of earrings.

The Two Systems: Karat vs. Millesimal Fineness

The US uses the karat system (10K, 14K, 18K). Much of Europe and the international gold trade uses millesimal fineness, a three-digit number representing parts per thousand. Both systems appear on jewelry sold in the US, especially imported pieces.

Complete Hallmark Reference Table

Here’s every common gold hallmark with its purity and today’s price per gram.

Stamp	Karat	Gold Purity	Price Per Gram Today	Common Use
417	10K	41.7%	~$59.54	Budget jewelry, children’s pieces, US market
585	14K	58.3%	~$83.37	Most US engagement rings, chains, everyday jewelry
750	18K	75.0%	~$107.20	European fine jewelry, luxury pieces
916	22K	91.7%	~$131.02	Indian gold jewelry, some coins
999	24K	99.9%	~$142.93	Investment coins, bars, bullion

What If There’s No Stamp?

Older pieces, handmade jewelry, some imported items, and gold from certain countries may lack a hallmark. The absence of a stamp doesn’t mean it isn’t gold; it just means you can’t verify purity visually. A jeweler can test it with an acid test (inexpensive, about $5 to $10) or an XRF (X-ray fluorescence) analyzer (non-destructive, very accurate).

Stamps That Mean It Is Not Solid Gold

Watch out for these markings; they indicate plated or filled gold, not solid gold.

GP or GEP: Gold Plated / Gold Electroplated. A thin layer of gold over base metal, with melt value that’s essentially zero.

GF: Gold Filled. More gold than plating, but still a thin layer bonded to a base metal, with low melt value. See 14K gold filled price per gram for exactly what this is worth.

RGP: Rolled Gold Plate. Similar to gold-filled and not solid gold.

HGE: Heavy Gold Electroplate. Thicker plating, but still not solid gold.

Only pieces stamped 10K/417 through 24K/999 are solid gold and have meaningful melt value. Use the gold calculator to find out what your solid gold piece is worth today.

Why This Matters When Using a Gold Calculator

When you enter data into any gold calculator, including ours, the karat input determines the purity multiplier. If you enter 14K for a piece that’s actually 10K, the calculator will overestimate the melt value by about 40 percent. Read the stamp carefully before calculating.

Frequently Asked Questions

What does 585 mean on gold jewelry?

585 is the millesimal fineness mark for 14 karat gold, meaning 585 parts pure gold per 1,000, or 58.3% pure. It’s the European and international equivalent of the US “14K” stamp, and both indicate the same purity.

Can a hallmark stamp be faked or wrong?

Yes. Stamps can be applied fraudulently, especially on older or lower-quality pieces, and they can also simply be worn down to illegibility over time. If you have any doubt, an acid test or XRF analysis confirms the actual purity regardless of what’s stamped.

What’s the difference between a GF and GP stamp?

GF (gold filled) has a meaningfully thicker layer of gold mechanically bonded to a base metal core, giving it some real, if small, melt value. GP (gold plated) uses an extremely thin electroplated layer with essentially no recoverable gold. Neither is solid gold, but GF pieces are worth more than GP pieces as scrap.

Does a higher karat always mean better jewelry?

Not necessarily. Higher karat means more gold content and higher value, but it also means a softer, less durable metal. See 14K vs 18K gold for how purity and durability trade off against each other in practice.