These marks — which may be found inside, on the back, or near the clasp, depending on the type of jewelry — are intended to tell you how pure the gold used in that piece of jewelry is, or if it contains gold at all.  

Because solid gold is relatively soft on its own, jewelry crafted from pure gold isn’t considered safe for setting stones and wouldn’t stand the test of time. It must be mixed with other metals to create strength, balance and workability. 

Mixing gold with other metals is also what creates different gold colors, such as yellow gold, rose gold, and white gold. Different gold “recipes” result in different colors, but also in different hardnesses. Gold purity is measured in karats, (not to be confused with carat, the unit of weight used for diamonds and other gemstones), and one karat is 1/24 of the whole. 

For example, 18K yellow gold has 18 karats (or parts) of fine yellow gold and 6 parts of other metals. 20K rose gold would have 20 parts yellow gold, and 4 parts of copper, zinc, or silver alloys to impart rosy tones. 

Gold Purity Marks

You’ll notice that your gold jewelry is stamped with a two-digit number followed by the letter “K” or sometimes a three-digit number indicative of the percentage of gold in the item. 

Here are some common markings: 

  • 18K or 14K: These tell you how many gold parts there are in relation to the other metals mixed in. For example, an etching or stamp that says “18K” means the jewelry is made up of 18 parts gold and 6 parts of another metal. 
  • 750 or 585: These marks are more common outside the United States, and tell you how much gold is present out of 1000 particles. 24 karats of gold would be equivalent to 1000. A stamp of 585 means that 585 parts out of 1000 (or 58.5%, the same as 14K) are gold. 

Watch for these markings, which tell you that there isn’t any gold in the actual jewelry piece itself:

  • GP: This stands for “gold plated” and means that the jewelry has a thin layer of gold on top of another metal (usually copper, silver or brass). Sometimes the mark “GP” will be accompanied by the karat weight of the plating, such as “18KGP”. The percentage of gold in a gold-plated piece is usually 0.05% or less. Eventually, the gold will tarnish or rub off. 
  • GF: This indicates the jewelry is “gold filled,” meaning there is a thin layer of gold bonded inside a different base metal. 
  • HE or HGE: If you see this marking, it means the gold in your jewelry has been layered on using a high grade electroplating process. Just as with GP and GF, these designations tell you the piece doesn’t actually contain gold. 

Other Markings and Symbols on Gold Jewelry

In addition to marks that provide valuable information about the gold content in your jewelry, there are other marks that can help you ascertain quality. 

Maker’s marks include company names, logos, designer signatures, or other indications about the jewelry creator. You may also see serial numbers. All the pieces we create at Coffin & Trout are engraved with “C&T” and our trademark, in addition to purity marks. 

Other symbols and letters help tell the story of where the jewelry item originated, who made it, and even the date it was made. For example, jewelry made in the UK is required to bear hallmark stamping with the symbol of the pertinent Assay Office Mark to indicate which regional office it came from. 

Bottom line

The marks on your gold jewelry matter and should be considered in your buying decisions, particularly if you’re looking for an heirloom-quality piece or something that you wish to wear frequently. The best way to know you are buying quality jewelry, no matter the metal or gemstones you select, is to have a relationship with a jeweler you can trust. 

Where you purchase your gold jewelry from matters. All the precious metals, including the gold, in our jewelry are selected based on quality and longevity. Visit us to learn more about how we select our gold, as well as the exquisite craftsmanship that goes into every piece.