Know Your Karats - What You Need to Know Before Buying Gold Jewelry

Understanding karats and alloys will help you make the best choice for your next jewelry purchase. It can also help you understand the value of jewelry you already have.

Let's demystify all those confusing terms and markings plus mention the benefits and drawbacks of different alloys.

What does karat mean?

The words karat and carat come from the same ancient roots. Karat later came to have a specific meaning to describe the amount of pure gold in an alloy. Carat now usually refers to the weight of gemstones.

"The word "karat" comes from the Greek word "keration," meaning "small weight." It was originally used to describe the weight of a single seed from the carob tree, which was a common unit of weight in the ancient world.

In the context of precious metals, "karat" refers to the purity of gold or platinum. The karat system was developed in the Middle Ages in Europe, and it is still used today to indicate the amount of pure metal in an alloy."

-quoted from etymologyworld.com from their article: karat etymology online, origin and meaning

photo: seed pod of carob tree

How are the most common karats marked and what do they mean?

Karats can be expressed as a number followed by a K (ex. 14K) or a 3-digit number (ex. 585). Sometimes you might see Kt or KT instead of just K but they all mean the same thing.

Pure gold consists of 24 karats or 24 parts in the whole. 18K is 18 parts pure gold, 6 parts other metals to total 24 parts. 14K is 14 parts pure gold, 10 parts other metals and so on.

photo: typical example of the 14K version of 14 karat stamp

The 3-digit number is a little more straightforward to understand. This is the millesimal fineness scale.

This scale tells you how many parts per 1000 is gold. 18K is 75% pure gold and 25% other metals. The stamp in this case would be 750 for 750 parts gold out of 1000. 

photo: stamp inside a ring "585" meaning 58.5% gold or 14K

Here's a list of the most commonly seen karats:

9K or 375 is 37.5% pure gold

10K or 417 is 41.7% pure gold

14K or 585 is 58.5% pure gold

18K or 750 is 75% pure gold

22K or 917 is 91.7% pure gold

24K is 999 or 99.99% pure gold

If it's marked with a karat stamp does that mean it's definitely gold?

While rare, there are cases of unscrupulous manufacturers inaccurately marking their products. A common example is chains made of heavy metal like steel. These chains are often plated with gold and marked 14K or similar.

The other most common example is coins or bars marked as though they are pure gold but are in fact gold plated over a base metal. If the deal is too good to be true, it probably is. Best advice is to always purchase from reputable stores!

There are also cases in which there is a karat stamp but the letters and/or numbers that follow mean that they are not solid gold.

Gold Filled:

Refers to a thicker layer of gold usually over a brass base. If you see markings such as 1/20 14K, 1/10 10K, GF, 14KGF then the piece is not gold all the way through. The fractions refer to the ratio of gold to the weight of the entire piece.

For example, 1/20 14K means that one twentieth of the piece is 14K gold and the rest is likely brass. Eventually the gold layer will wear off especially on the highest spots and you will see the duller brass underneath. We see lots of examples of this technique in vintage jewelry, but it is still manufactured today. Its primary benefit is the lower price point and is a bit more durable than gold plated jewelry. 

photo: clasp stamped "1/20 12K GF" meaning 1 twentieth of the total weight is 12K gold and the rest is brass

Gold Plated:

Refers to an extremely thin layer of gold deposited onto any number of base metals. If the plating is over a base metal, there is usually not a karat stamp. If there is a stamp it may be a karat followed by GP which stands for gold plated. This layer of gold plating is so thin that it will wear off very quickly. 

Vermeil:

When the base metal is sterling silver and plated with gold, it's referred to as vermeil. Manufacturers usually stamp this 925 (92.5% silver) or sterling silver, which only refers to the base of silver.

Rolled gold:

According to the Jewelers Mutual website, "RG or RGP: An “RG” or “RGP” mark stands for “rolled gold” or “rolled gold plate.” Rolled gold contains 100 times more gold than average gold plates; therefore, it is of higher quality than a jewelry item labeled as “gold plated.”" - quoted from Jewelers Mutual. In our experience here at Jewelsmith, we do not encounter this stamp very often.

Electroplating:

GE, GEP and HGE all mean that the piece has been plated using an electric current. HGE means that the layer of gold deposited by this method is thicker.

Fun Fact: Many real gold coins are marked with the weight of the pure gold content but will weigh slightly more. This is because they also have a tiny bit of other metals to give them more durability and will test as 22K even when they contain the marked amount of pure gold.

What is an alloy? Let's geek out!

An alloy is a combination of two or more (usually) metallic elements. Pure gold is a very soft and buttery metal. It can easily be bent with fingers alone unless it's very thick or hardened. Other metals are added like copper, silver, nickel, palladium, zinc, silicon to create alloys with different colors and to make it stronger, more durable and easier to work with.

What metals make gold different colors?

Rose gold:

Copper is added to lend it's orangey-pink color to the pure gold. See more examples of rose gold.

photo: rose gold ring with Sea of Cortez mabe pearl and diamond accent

White gold:

Nickel or Palladium are added to "bleach" away the yellow. Nickel white gold tends to be whiter, but many people have an allergy to nickel. Palladium white gold is a more yellowish or brownish-gray color. Another advantage to palladium white gold is that far fewer people have an allergy to palladium than to nickel. 

See more examples of white gold jewelry.

photo: 14K palladium white gold diamond pendant

Green gold:

Silver and copper plus pure gold together make a slightly greenish whitish alloy. 

photo: custom created green and white gold green garnet bypass ring

What are some of the pros and cons of the most popular karats and colors of gold?

9K/375: 

pros-

• low cost

cons-

• brittle and prone to cracking
• yellow alloys - dull brownish yellow color

10K/417:

pros-

• low cost
• very hard meaning that raised details stand up well to wear such as letters on class rings
• white alloys - very white
• rose alloys - very rosy

cons-

• brittle and prone to cracking
• yellow alloys - very pale-yellow color

14K/585:

pros-

• good cost to durability balance
• good balance of hardness to brittleness, meaning it holds up to wear well
• rose alloys - nice rosy color

cons-

• yellow alloys - pale yellow
• white alloys - off white (nickel) to yellowish white (palladium)

18K/750:

pros-

• yellow alloys - excellent balance of hardness to brittleness
• yellow alloys - rich yellow color
• white alloys - whiter than 14K white

cons-

• costs more than lower karats
• rose alloys-pale pink
• rose alloys - difficult to get a quality casting without special equipment

22K/917:

pros-

• rich yellow color
• less likely to crack

cons-

• higher cost
• fairly easily bent and dented

24K/999:

pros-

• rich gold color 

cons-

• higher cost
• very soft - easily bent and dented

Fun Fact: All alloys and pure gold can be hardened or softened within a range. 18K nickel white can be softened to a point but never as soft as pure gold for example.

Any process that compresses the metal such as hammering will make the gold harder and less likely to bend. A process called annealing which involves heating and cooling the metal to specific temperatures at specific rates will soften the metal after it's been hardened. Hardening can also be done with a specific heat process.

How do I know if it's really gold?

Find a jeweler that you can trust and have them test your metal. Read their reviews, see how long they've been in business, get recommendations from people you know and always trust your gut.

Most common testing methods:

• Acid: different strengths and combinations of acids such as nitric and hydrochloric are used to determine the karat of gold or if it is a base metal instead
• Electronic: various models of electronic tests are available that test the conductivity of the metal
• X-ray: Uses x-rays to measure atomic characteristics of elements

Can I test my gold at home?

Acid Testing:

Acid testing is not recommended for home use. The acids can burn skin, cause eye damage, and lung damage if fumes are inhaled. Interpreting the results can be tricky. For example, palladium white gold will test a karat higher than it truly is. A spot must be sanded or filed to reveal the true metal underneath. Testing the plating on the surface will give you a false result.

The fumes will also accelerate rusting of steel nearby and will only be effective for a few months after opening, even if kept in optimum conditions. Handling should be done in controlled and safe conditions by a professional!

Electronic Testing:

While electronic testing machines are widely available for purchase, interpreting the results can be tricky without experience. A small area must be sanded or filed away so that if it is plated or gold filled, you're not just testing the plating.

White gold is especially tricky to interpret. For example, palladium white gold alloys will test a karat higher than they are because of the palladium content. What makes it even harder is the alloy is usually not marked whether it contains palladium or nickel. Pure palladium can test as higher karat gold, usually 18K. 

X-Ray Testing:

X-Ray testing is cost prohibitive even for many jewelers, much less home testing. Models can run in the tens of thousands! That being said, they can determine more than just the purity of the metal. They can tell you the types and percentages of each of the metals in the alloy.

Your Best Bet:

We suggest you take your jewelry to a trusted expert for testing. This way, you avoid making a costly mistake at home.

Can I change one color or karat of gold into another?

Yes! We offer a service called "Same Molecule Refining." This process extracts the pure gold from your jewelry regardless of its color or karat and returns pure 24K gold.

Traditional refining is done in huge lots. While you may get a tiny amount of your original pure gold returned to you, it's mixed with everyone else's. With "Same Molecule Refining," the refining is done with your gold only so you get only your pure gold returned.

For example, you can transform your grandparent's white gold wedding rings into a rose gold engagement ring, keeping the sentimental value and adding flexibility. There is a minimum of 1 ounce to send in for this service.  

As I write this article in August 2025, the price of gold is near all-time highs. Market prices are just above $3300 an ounce. Since prices are high, refining your existing gold makes a lot of sense right now, plus it's a great time to trade in your old gold. You can use it for credit toward a purchase, custom-made jewelry or you can receive a check. 

Kitco is a fabulous resource for tracking the metal market prices. The chart above is a screenshot from their website that shows gold prices over the last 5 years.

Tap the link below to see this chart in real time:

Gold Price Today | Price of Gold Per Ounce | 24 Hour Spot Chart | KITCO

Conclusions:

• Being familiar with the different terms and markings can help you be a savvier shopper.
• Find a jeweler that you trust both to make purchases from and to test metal that you have.
• Choose a karat and color of gold that matches your lifestyle and aesthetic preferences.
• Gold is one of the most recycled materials and has been for thousands of years. It can be melted, reformed, mixed and separated over and over. Consider trading or Same Molecule Refining your old gold.

 

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