Understanding Gold Purity: 9K, 10K, 14K, 18K, 22K, 24K

Updated on September 27, 2018
The stamp on this piece of gold could indicate what use it's intended for and how many, if any, other metals were added to it.
The stamp on this piece of gold could indicate what use it's intended for and how many, if any, other metals were added to it. | Source

Many of us, at one point or another, will find ourselves shopping for gold in the jewelry department of a department store or in a jewelry store.

If you've ever gone shopping for jewelry, you are probably quite familiar with the word “karat” as applied to gold. The higher the karat, the more expensive it will be. But have you ever wondered why?

The short answer is that higher karats mean more gold, but there’s more to it than that.

What does it all really mean? And what is all of that fine print stamped into your piece of gold? What are karats really? How do you know how pure that gold really is? This article will answer all of these questions and more.

What Are Karats?

Karats, spelled "carats" outside of North America, are the little numbers stamped on a piece of gold in the format of "xxK" or "xxKT". The numbers refer to the type of gold and to the actual gold content in the particular piece of jewelry.

Here’s more information on karats:

  • Karat is a measurement of the ratio of gold to other metals or alloys.
  • Karats are measured on a scale from 0 to 24.
  • The higher the karat number, the more gold there is and the less other metal content.
  • Other metals and alloys could include copper, nickel (not common anymore), silver, or palladium.

With this in mind, 24-karat gold is the purest gold you can buy.

Why are other metals added to pure gold?

Gold is quite malleable in its pure state. Other metals are added to strengthen it and in some cases to enhance color. An example is when copper is added to create rose gold.

Source

How to Use Karats to Measure Gold Purity

Knowing the number of karats is key to calculating the gold content on your own. Here is how to use the number of karats to figure out how pure your piece of gold is.

Say you purchase a ring that is 14K gold. Since the number amount of karats you can have is 24K, divide the 14 Karats by the 24. You will get .583. This means that the gold is 58.3% pure.

Gold Purity Conversion Chart

Number of Karats
Parts of Gold
% of Gold Purity
Millesimal Fineness
9K
9/24
37.5
375
10K
10/24
41.7
416/417
12K
12/24
50.0
500
14K
14/24
58.3
583/585
18K
18/24
75.0
750
22K
22/24
91.7
916/917
24K
24/24
99.9
999

As you can see in the above chart, "millesimal fineness" refers to the percent of gold, while karats refer to the ratio of gold to other metals in the piece. Converting between the two is rather easy when you convert the percent to fraction form, or vice versa.

Gold Purity Terminology

What is gold "fineness"?

The measure of gold purity, or fineness, refers to the gold-to-metal additive ratio.

Let’s take a look at a few terms that you may come across when studying about or shopping for gold:

  • Assay: A test which determines metal content and quality.

  • Bullion: Precious metals in a bulk, uncoined form such as gold bars, considered in mass rather than value.

  • Carat: Not to be confused with Karat in North America, a Carat is a unit of measurement used for precious stones. Equal to 200 milligrams. Outside of North America, Carat is used in the same context as Karat.

  • Ductile/Ductility: How capable a metal is to being deformed using tensile force. Ex. Ductile materials can be stretched into thin wires without fracture.

  • Hallmark: A symbol or mark stamped on a piece of precious metal which certifies its standard of purity.

  • Karat: Unit of measurement for the fineness of gold, with the higher numbers containing more gold and 24K being the finest.

  • Malleable/Malleability: How capable a metal is of being deformed using compressive force. Ex. Malleable metals can be hammered or rolled into thin sheets.

  • Millesimal Fineness: A system used to show the purity of precious metals by parts per thousand rather than karats.

  • Troy Ounce: 31.1034768 grams, or approximately 1.09714 standard “avoirdupois” ounces.

  • Troy Weight: A system of measurement used for gemstones and precious metals, where a full Troy Pound consists of 12 “troy” ounces rather than the 16 “avoirdupois“ ounces in a standard pound.

What Do the Stamps on Gold Mean?

Here’s a list of stamps that you might find on a piece of gold and what they mean.

  • EPNS If someone is trying to sell you a piece of “gold” marked “EPNS,” run away. It stands for “Electroplated Nickel Silver” which is silverplate. This means the piece is not gold and it’s worthless.

  • EPBM Again, if someone is trying to sell you “gold” marked “EPBM,” go elsewhere. This stands for “Electroplated Britannia Metal” which is not gold at all. It is a silver/tin alloy consisting of copper, lead, or zinc.

  • GE: Gold Electroplate This is a piece consisting of a base metal, often brass, with a certain thickness of gold electrolytically deposited onto the base. The minimum standards require to be considered GE is 7 millionths of an inch and at least 10K gold as the plating.

  • HGE The also refers to Heavy Gold Electroplate, the same as GE above, but the "heavy" classification can only be made if the plating is at least 100 millionths of an inch.

  • GF This means Gold Filled is similar to gold plate but the gold is heat- and pressure-bonded to the base metal. It must have a minimum purity of 10K gold and the gold content must be at least 1/20th of the weight of the metal piece.

  • 375 This means the gold is 37.5% pure, or 9K. In the US, the minimum standard for gold is 10K. Many other countries allow this to be marketed as gold and it’s been used from jewelry to dental purposes.

  • 417 This means that the gold is 41.7% pure, or 10K. This type is very commonly used in jewelry in the US and is very strong. It is great for jewelry for those who work industrious jobs or who need something that will hold up.

  • 585 This means that the gold is 58.5% pure, or 14K. Good, strong gold but with a bit more gold than 10K.

  • 750 This means that the gold is 75.0% pure, or 18K. Much more pure than 14K, still has good strength with a wonderful balance in purity.

  • 916 This means that the gold is 91.6% pure, or 22K. This is probably the softest and most pure gold that you would want to have for a piece of jewelry.

  • 999 This means the gold is 99.9% pure, or 24K. This is the purest that you can buy, and although purity can be up to six nines fine, or 999.999, it’s highly rare to find it so pure. Such fineness in gold was last refined in the 1950s by The Perth Mint in Australia.

Does High Karat Mean Higher Quality Gold?

Purer gold does not necessarily mean better, it simply means more pure, worth more money, and more expensive. With gold, the phrase “less is more” can certainly apply. As stated earlier, the less pure the gold is, the more alloy metals it contains. Gold that is blended with more alloys is stronger. This may be preferable especially when it comes to jewelry, as 24K gold is very soft and not as durable. The lower the karats in that ring, the stronger it will be. Let’s compare lower and higher karats:

  • The lower the karat, the stronger it will be, while higher karat gold will be softer.

  • Lower karat gold is not very tarnish-resistant. Higher karat gold is much more resistant to tarnishing.

  • Lower karat gold is not worth as much monetarily. Higher karat gold is more valuable because it is purer.

  • Higher karat gold will appear more yellow.

Choose the purity level that makes the most sense for what you intend to use it for, whether it will be subjected to a lot of force, and your personal preferences.

Source

Common Uses for Gold

Although a bit more than 75% of the gold used every year is made into jewelry, there are other uses as well. Gold is very flexible and is used in many different industries for various purposes, depending on the purity. Gold is used in many industries from jewelry-making to food.

  • Coins/bullion: Currency is one of the greatest uses as gold will always hold value even if the dollar collapses. Take American Buffalo coins, for example; they are 24K gold, pure as pure can be!

  • Computers/technology: Since gold is a terrific conductor of electricity, it is often found in computers and technology. You will even find small amounts in cell phones, about $.50 worth!

  • Aerospace: Being such a great conductor, gold is used in various circuit boards for spacecraft and also as a shield to keep the temperature of the spacecraft stable.

  • Dental: We’ve all seen rappers with golden grills. Gold is not just for looks, though! It’s highly useful in the mouth and can be found in fillings, crowns, bridges and other dental applications.

  • Medical: Not only is gold used in medical appliances and instruments, but it is also literally used as a “drug” for medical purposes for various conditions, including radiation treatment for certain types of cancer!

As far as food goes, don’t go eating that engagement ring in a life or death situation! Gold leaf is often used as a decorative, but edible garnish for food since the food-grade gold is non-toxic. You may also be familiar with the liquor Goldschläger, which contains visible pieces of gold flakes. So forget the cake, you can have your gold and eat it too!

Purpose of Stamps or Hallmarks

While you may come across some pieces of gold that are not stamped with purity, most gold, especially jewelry, will come stamped with what's called a "hallmark" as a reference and even a selling point. All gold found in a jewelry or big box store in the U.S. will be stamped. While U.S. gold standards enforce the stamping of purity somewhere on the jewelry, you may still come across a piece of jewelry that is not marked, such as very old or handmade pieces.

The types of stamps and any laws behind stamping jewelry will vary by country, and if you come across an unstamped piece of gold that is marketed as of a certain purity, it’s best to proceed with caution and test the gold using a gold testing kit.

In some instances, jewelry that is stamped as being a certain purity can turn out to be fake or misrepresented. This is more common when ordering online from a foreign country. Usually in cases like these, the price is a good indicator of faux metals. The old adage “you get what you pay for” holds true, especially when dealing with precious metals. Should you find yourself in the receiving end of such a situation, it’s a good idea to file a report with the Federal Trade Commission (FTC).

What is a hallmark?

If you’ve shopped for jewelry in Europe, or even imported pieces over in the U.S., chances are you've come across a few strange images on the jewelry which may or may not be accompanied with an actual purity number stamp. These are called hallmarks and do not need to be accompanied by a specific purity stamp. If you know the hallmark, you will know just which purity is being guaranteed.

The types of symbols you will come across will vary by country and time period. In other words, not only are hallmarks great for identifying the type of gold or precious metal used in the piece, they also help date the jewelry.

Here are some clues to look for:

  • An octagon shape in the hallmark indicates gold.
  • If the hallmark includes a three-digit number, this is most likely the purity of gold. For example, if the number “585” is stamped inside the octagon, this indicates that you have a piece of gold that is 14K, or .585 in purity.
  • Other symbols stamped into the gold indicate which company submitted the piece for hallmarking, and which assay office tested and stamped the hallmark of approval. Hallmarks give you peace of mind that the gold you bought is genuine and has been tested and certified.

How to Test Gold Purity

© 2015 Dennis Ebris

Comments

    0 of 8192 characters used
    Post Comment

    • profile image

      Izaak 

      6 weeks ago

      Very useful article. Congrats.

      But Ct y K are used worldwide as the U.S has also adopted it. It is an ancient convention based on...seeds.

      Carob seeds. They noticed that they use to be very similar and weight the same.

      Any serious dealer will know it(and I am from Brasil, our clients came from all over Europe, and carat(weight) abbreviated ct of a gem, except perls, that have another way to determine the quality and Karat (K) is for the amount of gold in the alloy. Everywhere.(Not sure about the UK.)

    • profile image

      Aries Pi 

      2 months ago

      Hello I found a ring with marking

      357 f2702

      I google it says 357 is gold

      How about f2702? What that stands for?

      Is the ring a saw can be pawnable?

    • debris profile imageAUTHOR

      Dennis Ebris 

      6 months ago from Florida

      It's actually just some acid solutions. You can get them on Amazon or from most jewelry supply catalogs.

    • profile image

      Theresa Dye 

      7 months ago

      My grandmother was born in 1872 and married in 1890. I inherited her gold wedding band. It is 1/4 inch wide and stamped inside "SOLID GOLD" inside a stamped rectangle. It is very soft. I don't know if she got it when she got married in 1890 or at a later time. Do know she had it all my lifetime (82 yrs.) and when my mother was living (born 1901) she said she thought she had always had it. I'm just curious about the approximate age and the "Solid Gold" marking. Anything you can tell me would be great.

    • profile image

      craig 

      10 months ago

      There was no mention of Vermeil in your definition.

    • profile image

      Najbu 

      14 months ago

      Simply defined, very informatic

      Thanks

    • profile image

      Dana Ratliff 

      21 months ago

      Have a 1910 European ring with an owl stamped in it, appears to be 18kt gold?

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, owlcation.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://owlcation.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)