Understanding the Gold Karat Scale
Did you know that you can transform a single ounce of gold into a thread that is over 50 miles long? Jewelry makers have long prized this malleable yellow metal because of its excellent workability. Gold never tarnishes, making it a perfect choice for jewelry.
However, gold’s excellent workability comes at a price. Pure gold is a soft metal according to the Mohs hardness scale (the standard measure of mineral hardness.) Over time, jewelry made from pure gold is prone to scratches and malformations. To combat this, many jewelers purposefully mix gold with another metal, creating a stronger gold alloy.
Metal alloys are made when two different precious metals are mixed together. In general, alloys are stronger than their pure components. This is because the two metals have differently sized atoms, blocking the movement of atoms, resulting in deformation. Mixing other metals with gold results in a strong metal that can be easily manipulated to form the intricate structures needed in jewelry.
The metals most commonly mixed with gold for jewelry include silver, nickel, iron, zinc, and copper. The resulting combinations may retain gold color or take on a new color based on how the components interact. Creating a new gold alloy can alter some characteristics other than strength and color. When gold is alloyed with copper or silver, it may stain some individual’s skin. Alloys with nickel or zinc may cause an allergic reaction.
It’s possible to keep the amount of gold constant while altering the quantity of other metals in the alloys. This gives jewelers and metalsmiths the ability to create a recipe for a gold alloy that has the perfect characteristics for their desired purpose. This may be a unique color, impressive increases in durability, or an upgraded luster. Top brands like Rolex have developed these recipes to create proprietary alloys that set their pieces apart from the competition.
What Is a Gold Karat?
Since gold is commonly mixed with one or more metals in jewelry pieces, the karat system was developed to indicate how much gold the piece contains. Gold that is 100% pure is 24-karat gold. This is because one gold karat is 1⁄24 part of the whole. You can think of gold karats as a way to measure purity.
The unusual scale for gold karats comes from medieval times. In the Middle Ages in Germany, a very common gold coin called a mark was used as currency. The mark contained 4.8 grams of pure gold, which is equal to 24 karats. From this, the modern gold karat system was based.
While it is technically possible for gold to range from 1k to 24k, in the jewelry industry, there are three common karat levels: 18k, 14k, and 10k. Before 2018, any item containing less than 10 karats of gold could not be sold as gold. However, an update to the FTC regulations in 2018 allowed for the marketing and sale of 1k gold.
Any jewelry made from 24k gold contains 100% pure gold. This can make the pieces more expensive, as well as more prone to damage. A piece made from 24k gold will bend, warp, and scratch if worn daily.
Pure gold has a rich yellow-orange shine that has made it popular for centuries. However, when used in jewelry, it may appear too bright or orange to those more familiar with lower-karat gold.
Mixed with silver and copper to improve durability, 18k gold is 75% pure. The amount of silver and copper can vary based on the jeweler’s preference and desired color. If you’ve purchased gold Rolex watches for men, then you’ve purchased 18k gold. Rolex uses 18k gold exclusively, for its shine and durability.
With jewelry made from 18k gold, you get the brilliance and warm color of pure gold. The alloy adds practicality to the jewelry pieces, making them significantly more durable than 24k gold. These pieces have a rich, yellow color that makes gold immediately identifiable. Unfortunately, 18k gold is still relatively easy to scratch and is more expensive than other alloys.
This gold alloy is still over 50% pure. In fact, 14k gold contains 58.33% gold, with the remaining 41.67% made from various metal alloys. Typically, zinc, nickel, or silver are used to improve the resistance to scratches while lightening up the rich yellow color.
This is the most popular type of gold used in jewelry within the U.S. It offers a balance of durability and affordability. Some individuals may prefer the softer yellow color compared with more pure gold jewelry.
Pieces made from 10k gold contain 41.7% pure, which is still a significant amount. Zinc, copper, nickel, and silver can be used to create a 10k gold alloy. The proportions of each metal affect the color, strength, and shine of the final piece.
An advantage of 10k gold is that it weighs less than the other gold allows. This makes it an ideal material for men’s iced-out chains. It adds shine and strength while keeping the piece lighter for your comfort.
Some 10k gold alloys may contain significant amounts of zinc and nickel. This can cause issues for individuals with sensitive skin who react to those metals. This doesn’t mean that those with sensitive skin shouldn’t wear 10k jewelry. Many other hypoallergenic metals, such as palladium, can be used in creating 10k gold alloys.
The reaction between different metals with gold can create unique colors. White gold is the most common example of this. However, more gold colors are possible, such as red, pink, green, and even blue.
Adding up to 20% nickel to gold with some copper and tin creates white gold. This unique alloy closely resembles silver, though it can contain up to 75% gold. White gold can be alloyed with a small amount of platinum to increase its durability.
Rose gold occurs when the right amount of copper is alloyed with gold. However, because copper has the same Mohs rating as gold, silver and zinc are also added to increase the durability and soften the tone of the metal. The amount of gold also affects the final product’s color, with more gold yielding a more copper-toned metal and less gold yielding a soft champagne pink.
A gold alloy that has a significant amount of silver turns green, though, to an untrained eye, green gold may look like slightly tarnished gold, which is why many jewelers prefer to make gold alloys with nickel and silver. The combination reduces the quantity of silver required and reduces the chances that gold will turn green.
Iron is not typically alloyed with gold, as it is prone to oxidation. However, the unique combination of gold and iron creates a metal that transforms from shiny yellow gold to a deep blue color when exposed to heat and air.
All colored gold alloys contain specific ratios of gold. This allows them to be rated on the same gold karat system as yellow gold. If you are browsing jewelry and see a 14k white gold chain for men, you’ll know the piece contains 58.3% gold.
Stamps and Marks
There are strict laws governing gold purity labeling in the U.S. Gold items can’t be labeled as “solid gold” unless the piece is 24k gold. All other pieces must disclose the amount of gold in the piece. This makes the use of the karat system a legal requirement for jewelers.
You may have noticed a small stamp on the inside of rings or the underside of necklaces. This purity stamp indicates the gold karat purity of the piece. If stamped, the gold contained in the jewelry piece must be within three parts per thousand of the karat standard. There should be a second stamp of the maker’s registered trademark close to the purity stamp. This indicates that the maker is liable for the purity of the piece.
An alternative to stamping the karat value of gold is to stamp the fineness. Fineness is another way to express the purity of gold. It refers to the parts per thousand of gold. The fineness label for 18k gold is 750.
New Gold vs. Old Gold
The age of your gold doesn’t classify it as new gold or old gold. New gold is a term used to refer to gold that has been refined to current standards. This means new gold reliably matches current purity standards. New gold could be a piece of jewelry, or it could be a bar of raw material that a jeweler is planning to use to create their next piece.
Old gold refers to other gold items that might have had their purity altered. This might be due to repairs or modifications over time. Solder matches the color of gold and is used to join pieces together. Highly worked pieces may contain extra solder that reduces the overall karat weight of the piece.
Jewelers will often send old gold pieces out to a refiner before creating new items with the gold. You can also sell your old pieces of gold jewelry to a refiner for them to melt and recycle. The refiner removes impurities that may cause issues during casting and return gold with a reliable karat weight. This allows jewelers to craft new pieces from gold that may have been mined decades before.
How to Choose the Best Type of Gold
The right type of gold for you depends on your priorities. There are advantages and disadvantages to gold at each karat level. When shopping for gold, these are the broad topics you’ll want to consider.
Some people are under the false impression that gold is a durable metal because it has been used in many applications. The reality is that gold is incredibly easy to damage due to its softness.
When considering a jewelry purchase, consider how strong and durable you want your piece to be. For pieces that aren’t for everyday wear and will be protected, 18k gold is a suitable option. However, if you want jewelry that you can frequently wear or in high impact areas such as your fingers or wrist, then a 14k gold piece offers the durability you need.
Gold purity affects the color of the final product. Color preference is personal and can depend on your skin tone. If you want a different color, such as white or rose, that may limit the karat options available.
While gold is hypoallergenic, the metals contained in gold alloys may irritate those with sensitive skin. Higher purity gold can prevent this problem for many individuals. Those with skin conditions should consider 18k gold as a quality option for their jewelry choices.
Zinc and nickel are typically the causes of skin irritation with gold jewelry. When shopping for gold jewelry, inquire about the gold alloy composition and avoid pieces with zinc or nickel. It’s possible to find quality pieces of 10k and 14k gold made from a gold and palladium or gold and platinum alloy.
Gold is a rare and precious earth metal. As such, the price of pure gold can be expensive. For those working on a tight budget, 10k gold offers the opportunity to have a quality piece of jewelry made from real gold at an economical price. Jewelry made from 14k gold offers a good balance between price, color, and durability.
Your jewelry should accentuate your personal style. While considering all the other factors, you ultimately want to pick a piece that you’ll be proud to wear. If you are a sports fan, choose pieces such as gold chains for athletes. Or, if you adore your pet, select a gold animal pendant to wear on your necklace.
Your Destination for Top-Quality Gold Chains
At Frost NYC, we only offer the highest quality gold chains. Every style can be customized to your perfect length in either white or yellow gold. From classic Cuban link chains to impressive iced-out chains, there’s an option for everyone. Treat yourself and add to your collection today.