Turn almost any piece of jewelry over and you'll find tiny numbers and letters stamped somewhere discreet — on a clasp, the inside of a ring, or a small tag near the end of a chain. Those marks are called hallmarks or quality stamps, and they're one of the most useful tools you have for understanding exactly what you're buying. Learn to read them and you'll never be fooled by a vague product description again. This guide decodes the stamps that actually matter: what 925, 750, 18K, and 316L mean, how plated-gold marks work, and how to tell a meaningful stamp from marketing noise.

Why Jewelry Is Stamped in the First Place

A quality stamp is a manufacturer's declaration of what a piece is made of. In many countries these marks are regulated, and even where they aren't legally required, reputable brands use them so buyers can verify materials at a glance. The stamp won't tell you whether a piece is beautiful or well made — but it will tell you the metal, the purity, and often the plating method. That's the foundation of knowing what you own.

One important caveat up front: a stamp is only as trustworthy as the company behind it. Cheap sellers sometimes stamp marks that don't reflect reality. That's why the stamp is one signal among several — alongside the brand's reputation, its return policy, and its reviews — rather than the whole story.

Gold Purity Stamps: Karats and the Three-Digit System

Solid gold is stamped one of two ways, and they mean the same thing expressed differently.

• Karat marks (K or KT): 24K is pure gold, 18K is 75% gold, 14K is 58.3% gold, and 10K is 41.7% gold. The lower the number, the more alloy metal is mixed in for strength.
• Three-digit fineness marks: The same purities written as parts per thousand. 999 is 24K, 750 is 18K, 585 is 14K, and 417 is 10K. A ring stamped "750" is solid 18-karat gold.

If the difference between these numbers matters to your buying decision, our full breakdown of gold karats explained (10K vs 14K vs 18K vs 24K) covers how purity affects durability, color, and price.

Silver Stamps: 925 and Sterling

The most common silver stamp is 925, which indicates sterling silver — 92.5% pure silver mixed with 7.5% other metals (usually copper) for strength. You may also see the word "STERLING" or "STER." Pure silver at 999 is too soft for most jewelry, which is why 925 is the practical standard. If a piece is stamped 925, it's genuine sterling silver.

Gold-Plated Stamps: GP, GEP, HGE, RGP and Vermeil

This is where buyers get confused most often, because plated marks look similar but mean very different things. When gold covers a base metal rather than making up the whole piece, the stamp usually includes an extra letter or two:

• GP (Gold Plated): A layer of gold over a base metal. "18K GP" means the plating is 18-karat gold — not that the whole piece is solid 18K.
• GEP (Gold Electroplated) and HGE (Heavy Gold Electroplate): Gold applied via an electroplating process.
• RGP (Rolled Gold Plate) and GF (Gold Filled): A thicker, mechanically bonded gold layer — more durable than standard plating.
• Vermeil: Gold plating over a sterling silver base, specifically. If you want the distinctions in depth, see our comparison of gold vermeil vs. gold plated vs. gold filled.

The takeaway: any letters after the karat number signal a plated or filled piece, not solid gold. That's not a bad thing — quality plating delivers the look of gold at a fraction of the cost — but you should know which one you're getting.

What "316L" Means — and Why It's on Better Steel Jewelry

If you see 316L stamped on a piece, that's a quality signal worth understanding. 316L is a grade of surgical stainless steel prized for its corrosion resistance, low nickel release, and durability. It's the same family of steel used in medical implants and marine hardware, which is exactly why it holds up to water, sweat, and daily wear without rusting.

At The Flaire, every piece is built on a 316L stainless steel core and finished with 18K gold PVD plating. That construction is what makes our jewelry waterproof, hypoallergenic, and tarnish-resistant. If you want to understand the material itself, our honest guide to whether 316L stainless steel jewelry is good goes deeper on the pros, the trade-offs, and who it suits.

What PVD Adds to the Equation

You won't always see it stamped, but the plating method is as important as the metal. PVD (physical vapor deposition) bonds the gold layer to the steel at a molecular level in a vacuum chamber, producing a finish that's dramatically more scratch- and fade-resistant than traditional electroplating. It's the difference between a color that lasts and one that wears thin within months. When a brand plates 18K gold via PVD over a 316L core, you get the appearance of gold with genuine everyday durability.

What a Stamp Can't Tell You

Stamps verify materials — they don't verify honesty or craftsmanship. A dishonest seller can apply a stamp that overstates a metal, and a stamp says nothing about how well a piece is finished or whether it will survive daily wear. This is why the smartest approach combines the stamp with other checks: read the full material description, confirm the brand offers a warranty and returns, and look at verified customer reviews. If you want a hands-on method for testing gold specifically, our guide on how to tell if a gold chain is real walks through the magnet, weight, and skin tests you can do at home.

Buying With Confidence

The best protection against a bad purchase isn't a stamp — it's a brand that stands behind what it sells. The Flaire publishes its full materials on every product page, backs every piece with a 1-year warranty and 30-day returns, and holds a verified 4.57★ rating from 4,500+ verified reviews. Browse the gold collection or the silver collection and you'll find the same transparency on every listing: 316L stainless steel, 18K gold PVD, and exactly what you're paying for.

Frequently Asked Questions

What does 925 mean on jewelry?

925 indicates sterling silver — an alloy of 92.5% pure silver and 7.5% other metals (usually copper) added for strength. It's the standard mark for genuine sterling silver worldwide.

Does 750 mean real gold?

Yes. 750 is the fineness mark for solid 18-karat gold, meaning the piece is 75% pure gold. It's the three-digit equivalent of an "18K" stamp.

What does 316L mean on a chain or bracelet?

316L is a grade of surgical stainless steel known for corrosion resistance, low nickel release, and durability. It's a quality signal indicating the piece is built to resist rust and hold up to water and daily wear.

What's the difference between "18K" and "18K GP"?

"18K" means the piece is solid 18-karat gold throughout. "18K GP" means it's gold-plated with 18-karat gold over a base metal — the plating is 18K, not the entire piece.

Can a jewelry stamp be fake?

Yes. A stamp is only as reliable as the seller applying it. Treat it as one signal alongside the brand's reputation, transparent material descriptions, a warranty, returns, and verified reviews — not as proof on its own.