Gold Hallmark Identification: What 10K, 14K, and 18K Really Mean

Gold hallmarks indicate purity based on a 24-part scale: 10K is 41.7% pure gold (marked “417”), 14K is 58.3% gold (“585”), and 18K is 75% gold (“750”). Authentic stamps also often include maker’s marks or assay office symbols. Any piece marked “GP,” “GF,” or “HGE” is plated, not solid gold.

Imagine you are at a dusty estate sale in Ohio, digging through a box of costume jewelry. You spot a heavy, dull yellow chain at the bottom. Your heart skips a beat. Is it just costume junk, or did you just find a solid gold necklace worth hundreds of dollars?

Knowing how to read the tiny stamps on that metal—the hallmarks—is the difference between a $5 trinket and a $500 payday.

How do I read gold purity stamps?

In the United States, the Federal Trade Commission (FTC) requires all gold jewelry sold as “gold” to be stamped with its karat quality. But these stamps can be tiny, worn down, or confusing.

Here is the breakdown of what you will see in the US market:

• 10K (or 417): This is the minimum standard for karat gold in the US. It is very durable but has a paler color.
• 14K (or 585): The most common alloy in American jewelry. It balances durability with that rich, classic gold color.
• 18K (or 750): Highly prized in the collector market. It is softer, heavier, and has a deep, buttery yellow hue.
• 24K (or 999): Pure gold. It is generally too soft for jewelry usage unless it is for investment bullion.

You might also see three-digit numbers. This is the European millesimal fineness system. If you see “585” on a clasp, that is 14K gold (58.5% pure). This is a great tip for finding underpriced items at thrift stores, as many clerks miss these number-only marks.

Identifying these marks manually can take hours, especially if they are worn or foreign. Using the Antique Identifier app, you can simply take a photo and get an instant result to help decipher what you are holding.

What if there is no stamp on my gold item?

This is a common issue with antique pieces, especially those made before the National Gold and Silver Stamping Act of 1906.

If a piece has been resized or repaired, the hallmark might have been polished away during restoration.

However, lack of a stamp does not automatically mean it is fake. You need to look at other factors like weight and oxidation. Gold is a dense metal; it should feel heavy for its size.

Real gold also does not tarnish or rust. If you see green or black spots where the metal rubs against skin, it is likely brass or copper reacting to the environment.

For unmarked pieces, professional authentication usually requires an acid test or an X-ray fluorescence (XRF) machine, which many antique dealers use to determine fair market value.

How can I spot fake gold hallmarks?

Counterfeiters are getting better, but they often make sloppy mistakes.

First, check the quality of the stamp. Genuine hallmarks are crisp, deep, and evenly spaced. If the “14K” looks crooked, shallow, or blurry, be suspicious.

Second, look for “weasel words” next to the karat mark. These indicate the item is plated:

• GP: Gold Plated
• GF: Gold Filled (thicker layer than plated, but not solid)
• HGE: Heavy Gold Electroplate
• RGP: Rolled Gold Plate

If you see “14K HGE,” put it back. It has practically zero melt value.

Understanding these distinctions is crucial for determining replacement value for insurance purposes. A solid 14K bracelet might be insured for $1,200, while a gold-filled version is worth $50.

What is the difference between white gold, rose gold, and yellow gold marks?

Surprisingly, the karat stamps are exactly the same. The difference lies in the alloys mixed with the gold.

• Yellow Gold: Mixed with copper and zinc.
• White Gold: Mixed with nickel, manganese, or palladium.
• Rose Gold: Mixed with a higher percentage of copper.

A “14K” stamp on a white metal ring means it is 14K white gold. However, if that white ring starts to look yellow over time, the rhodium plating is wearing off—a common condition issue that impacts the appraisal value.

This is similar to the material analysis we discuss in our guide on silver purity. For more on identifying precious metals in household items, check our article on Identifying French Provincial vs. English Colonial Furniture: An Expert’s Guide where we touch on metal hardware dating.

How does country of origin affect gold markings?

If you are browsing a high-end auction house or looking at items with European provenance, the marks change.

British hallmarks are incredibly detailed. They often include a purity mark, a city mark (like an anchor for Birmingham or a leopard’s head for London), and a date letter.

French hallmarks use symbols rather than numbers. An Eagle’s Head indicates 18K gold. A Clover Leaf indicates a lower standard like 9K.

These foreign marks can significantly increase the auction estimate because they allow for precise dating and attribution to specific makers.

Related Antique Identification Guides

Expand your expertise with these related guides: Fenton Glass Identification: How to Spot Rare Colors and Patterns, The 1800s Dresser Identification Guide: Dovetail Joints vs. Nails, Identifying French Provincial vs. English Colonial Furniture: An Expert’s Guide

Conclusion: Trust the Stamp, But Verify the Metal

Identifying gold hallmarks is a skill that pays for itself. Whether you are hunting for a bargain at a thrift store or inheriting a family heirloom, knowing the difference between 10K and 18K changes everything.

Always carry a loupe (a small magnifier) or use your phone’s camera. Look for the crispness of the mark and watch out for those sneaky “GP” letters. When in doubt, seek a professional condition report or use a digital tool to give you that initial confidence boost. Happy hunting!