What Karat and Purity Mean in Gold Jewelry
If you’re buying, selling, or evaluating gold jewelry, understanding gold purity and karat value is key. While pure gold exists, most jewelry is made from gold alloys to improve strength and durability. Fortunately, there are several reliable ways to determine how much real gold is in a piece of jewelry.
Why Gold Jewelry Isn’t Pure Gold
Pure gold—known as 24K gold—is extremely soft and malleable. While it’s valuable, it bends and scratches easily, making it impractical for everyday jewelry like rings, chains, and bracelets. To create wearable jewelry, gold is mixed with other metals such as copper, zinc, nickel, or palladium. This mixture is called an alloy, and the ratio of gold to other metals determines the jewelry’s karat value.
Understanding Karat Stamps on Gold Jewelry
Most genuine gold jewelry is stamped with a karat mark that indicates its gold purity. These stamps may appear as a karat number (such as 14K) or as a numerical purity code based on parts per thousand.
Common Gold Purity Markings
| Karat | Gold Content | Purity Mark |
|---|---|---|
| 24K | 99.9% | 999 |
| 22K | 91.7% | 917 |
| 20K | 83.3% | 833 |
| 18K | 75.0% | 750 |
| 14K | 58.3% | 583 |
| 10K | 41.7% | 417 |
These markings tell you how much of the piece is actual gold versus alloy metals.
What Does “P” or “Plumb” Mean on Gold Jewelry?
Some gold jewelry may include a “P” next to the karat stamp, such as 14KP. The “P” stands for plumb, meaning the piece contains at least the stated gold purity.
In the U.S., manufacturing tolerances allow slight variations in gold content. A plumb stamp assures the buyer that the jewelry meets or exceeds the stated karat value, which often increases confidence—and sometimes price.
What If There’s No Gold Stamp?
Not all gold jewelry is stamped, especially older pieces or custom-made items. If no stamp is present, you still have options:
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Professional testing: Most jewelers can test gold purity using acid testing, electronic testers, or XRF analysis.
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At-home testing kits: These kits typically use nitric acid and can provide a close estimate of karat purity. Always follow safety instructions carefully.
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Density testing: Some professionals use weight and displacement to estimate purity.
If a seller refuses to allow testing, that’s a red flag.
Final Thoughts
Knowing how to determine the purity of gold jewelry helps you shop smarter and avoid overpaying. By understanding karat stamps, purity markings, and testing options, you can confidently evaluate gold chains, rings, bracelets, and other jewelry.
Whether you’re buying new jewelry or assessing pieces you already own, gold purity knowledge puts the value—literally—in your hands.