Gold Purity Numbers: 375, 417, 585, 750 and What They Mean

You're looking at the stamp on a gold ring and you see "585" — no "K," no "gold," just three numbers. Or you find "417" on a necklace clasp, or "750" on an estate bracelet. These are purity hallmarks, and once you know the system, they tell you exactly how much gold is in the piece — more precisely than karat stamps in most cases.

The Purity Number System

Gold purity numbers represent parts per thousand. A piece stamped "750" contains 750 parts gold out of 1,000 — in other words, 75% pure gold. The math is straightforward: divide the stamp by 10 to get the gold percentage.

This system is used internationally — it's the standard in the European Union, UK (alongside hallmarking), most of Asia, and the Middle East. In the US, karat letters (10K, 14K, 18K) are more common but purity numbers appear on imported pieces, estate jewelry, and pieces made to international standards.

417 Gold Stamp

A 417 stamp means the piece is 10-karat gold — 41.7% pure gold, with 58.3% alloy metals (typically copper, silver, zinc, or nickel). 10K is the minimum gold purity that can legally be sold as "gold" in the United States.

Key facts about 417 / 10K gold:

• It is solid gold — not plated, not filled. The gold runs throughout the piece.
• It's the most durable common gold alloy because the high alloy content makes it harder and more scratch-resistant than 14K or 18K.
• The color is slightly less yellow than 14K or 18K — more of a pale gold, especially in white gold 10K alloys.
• Not legal as "gold" in the UK or Italy, which require minimum 9K (375) or higher standards.
• Common in children's jewelry, budget fine jewelry lines, and class rings in the US.

585 Gold Stamp

A 585 stamp means the piece is 14-karat gold — 58.5% pure gold. This is the most common fine jewelry standard in the United States and Canada, and widely used in European jewelry as well.

Key facts about 585 / 14K gold:

• Solid gold throughout the piece — 585 is a purity mark for solid gold, not plating.
• The sweet spot of the karat system: high enough gold content for rich yellow color, low enough alloy content to be harder and more durable than 18K for everyday wear.
• Less expensive than 18K or 22K gold of the same weight — you get more piece per dollar.
• The standard for most US engagement rings, wedding bands, and fine jewelry pieces.
• You may see "585" alone, or alongside "14K" — both mean exactly the same thing.

If you're buying estate jewelry and see "585" on the clasp or inner shank: it's solid 14K gold. Not plated, not filled. Real fine jewelry.

750 Gold Stamp

A 750 stamp means the piece is 18-karat gold — 75% pure gold. This is the fine jewelry standard for most of the world outside the US, and the preferred karat for luxury jewelry, designer pieces, and most European and Asian fine jewelry.

Key facts about 750 / 18K gold:

• Solid gold throughout — 750 is never a plating designation.
• The richest yellow color of the common karat standards — the warm, saturated yellow most people associate with "real gold."
• Slightly softer than 14K (10K alloyed vs 41.5K alloyed) — can show scratches more easily on high-wear pieces like rings.
• The standard for engagement rings in Europe, Australia, and most luxury brands worldwide (Cartier, Bulgari, Van Cleef — all use 18K / 750).
• When you see "18K GP" on a plated piece, the 18K refers to the karat of the thin gold layer, not a 750 solid gold piece.

Why Numbers Instead of Karat Letters?

The karat system (10K, 14K, 18K) is primarily an American standard. Most of the world uses the millesimal fineness system (the three-digit numbers) because it's more precise and unambiguous.

"14K" means 14 parts gold out of 24 — which works out to 58.33% gold. The hallmark "585" explicitly states 585 parts per 1,000 — 58.5%. The rounding makes these technically slightly different standards, though in practice they refer to the same alloy.

European Union law requires jewelry sold as gold to carry a millesimal fineness hallmark (375, 585, 750, etc.) rather than karat markings. UK hallmarking law includes its own assay office stamps alongside the fineness number. When you buy a piece imported from Europe, Italy, or the UK, you'll typically see numbers rather than K markings.

Purity Numbers on Plated vs Solid Jewelry

Purity numbers (375, 417, 585, 750, etc.) on their own always refer to solid gold. They describe the gold composition of the entire piece.

On gold-plated pieces, you'll typically see the purity number of the gold layer alongside a plating abbreviation or a base metal purity number:

• "750 GP" — the gold layer is 18K (750), plated (GP). Not solid 18K gold.
• "585 GF" — the gold layer is 14K (585), gold filled (GF). Not solid 14K gold.
• "18K 925" — the gold layer is 18K, base is 925 sterling silver. A gold-plated piece, not solid gold, but the best plated combination.

A 750 or 585 stamp alone — with no GP, GF, HGE, or other abbreviation — means solid gold. That's the tell.

Frequently Asked Questions

What does 417 mean on jewelry?

417 on jewelry means the piece is 10-karat solid gold — 41.7% pure gold. It's the minimum gold purity legally marketable as "gold" in the United States. 417 pieces are solid gold throughout (not plated) and are the most durable common gold alloy due to the high alloy content.

What does 585 mean on jewelry?

585 means 14-karat solid gold — 58.5% pure gold. It's the most common fine jewelry standard in the United States. A 585 stamp means the piece is solid gold throughout, not gold plated or gold filled. It's the same as "14K" — both designations describe the same alloy.

What does 750 mean on jewelry?

750 means 18-karat solid gold — 75% pure gold. It's the fine jewelry standard for most of the world outside the US, and the karat used by luxury brands like Cartier and Bulgari. 750 always refers to solid gold — it is not a plating designation.

What does 375 mean on jewelry?

375 means 9-karat gold — 37.5% pure gold. It's the most common gold standard in the UK, Australia, and Ireland. 375 is not legal as "gold" in the United States (which requires minimum 10K / 417), but it's solid gold and widely sold in European and Commonwealth markets.

Is 585 or 750 better for jewelry?

It depends on your priorities. 750 (18K) has richer color and higher gold content — preferred for luxury pieces and European fine jewelry. 585 (14K) is harder, more scratch-resistant, and more affordable per gram — preferred for everyday-wear pieces like engagement rings and daily-wear jewelry in the US. Both are solid gold; neither is "better" in absolute terms.

How do I know if my 585 stamp is solid gold or plated?

If you see "585" alone — no GP, GF, HGE, or other abbreviation alongside it — it's solid 14K gold. If you see "585 GP" or "14K GP," it's plated. The purity number alone, without any plating abbreviation, always indicates solid gold in the international hallmarking system.

What does 916 mean on jewelry?

916 means 22-karat gold — 91.6% pure gold. This is common in Indian bridal jewelry, Middle Eastern jewelry, and Southeast Asian fine jewelry markets. It's a very high-purity gold that's noticeably soft and more prone to scratching, but prized for its deep yellow color and high gold value.

→ Full stamp reference: jewelry stamps and hallmarks guide.