Karat vs. Carat: What's The Difference

We go over the difference between karats and carats.

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24k Gold Watch

When shopping for an engagement ring, you will need to know the difference between your karats and your carats. What does each signify? What is the difference between 24-karat and 18-karat gold? Although they sound similar, karat and carat are entirely different terms. It's essential to understand the difference.


The internationally recognized standard for measuring the weight of a gemstone or diamond is called the diamond carat. In comparison, karat refers to the purity of gold.


In jewelry-related texts, you'll see Karat and Carat interchangeably. Carat can be used to refer to either diamond weight or gold purity, while "karat" is only for gold purity. The spelling "carat" predates "karat." Karat was created to distinguish between the purity of gold and gemstone weight.


It is possible to have regional variations in spelling preferences. For example, the default spelling of "carat" in the UK and Australia refers to the purity of gold, while the US uses "karat." However, the term "carat," which is used to describe the weight of diamonds, is used everywhere in the world.


What does Carat mean?


 A larger carat means a higher price. As the carat is increased, the price goes up significantly. Contrary to popular belief, carat does not refer to the diamond size. Instead, it refers to the weight.


When discussing diamonds, carat refers to the weight of the stones when they are weighed using specially calibrated scales.


Where did the term Carat originate?


The history of carat's origins to express purity and weight is fascinating. Carat is an Ancient Greek word that means "carob seed." Carob beans were used for measuring tiny amounts and were also used to weigh pure yellow gold coins. Carat was very light in weight, so they were popular. However, with more advanced technology, we now know there is a lot of weight variation among carob seeds.


Is a Carat of Diamonds and a Carat of Gold the same thing?


Carat can be used to describe the characteristics of both diamonds and gold, as we have already discussed. However, they have different meanings, so it is vital to know the difference. 


What is a Carat Gold?


Because carat does not refer to the weight of gold, but the purity of the gold, gold carat is different from diamond carat.


Pure gold (24 carats) is too soft for jewelry. However, it has many desirable properties that make gold an excellent choice. It can be mixed with other metals (called alloys) to increase its strength, durability, and color while maintaining these properties.


Pure gold is 24 parts of 24-gold or 999 parts of 1000. Wait, 999 is 24 carats of gold. Why not 1000? It is impossible to achieve 100% purity in any metal. However, 99.9% is close enough to be considered the highest purity of 24kt gold.


Gold purity is called a fractional. So, other carats are determined based on their relationship to 24 (pure gold). A stamp is used to mark gold jewelry to describe the carat of the jewelry or its quantity.


18 Carat Gold


Also known as 18ct, 18kt, or 18/24, 18 parts pure gold out 24. 18ct is only 75% pure and can be stamped 18ct/18kt/750 (750 parts pure of 1000).


9 Carat Gold


Also known as 9ct, 9kt, or 9/24, 9ct is 9 percent pure gold. Half of 18 equals 9, so 9ct gold has half the gold as 18ct. The half of 75% equals 37.5%, so that 9ct can be stamped with either 9ct/9kt/375. 375 equals 9-carat gold.


The color of gold can also be affected by mixing it with other alloys. With the correct alloys, your jeweler can make gold pinkish or white. The carat specifies how much pure gold must be used to change the color of gold. For example, even 18ct white is 75% pure.


What Is Diamond Carat?


Carat refers to gemstones and is the measurement unit used to determine their mass.


Carat can refer to the weight of any gemstone, but diamonds are the most common gemstone carat refers to. Therefore, carat is an essential characteristic in determining the value of diamonds.

Common ways to express carat are "ct."


It is easy to explain diamond carat by comparing it to the system we use to calculate dollars and cents. However, we refer to points and carats. One hundred cents equals one dollar, and 100 points equal a one-carat diamond. A half a carat is 0.5 of the diamond. It can also be written 0.50ct. Ten points are equal to one-tenth of a single diamond, or 0.10ct. So a diamond that weighs one carat and has twenty-five points is 1.25ct. This is similar to the way we can say 10 cents or $0.10 for one-tenth of a dollar. Easy, right?


Total weight will indicate the number of small diamonds within a piece. These are either Total Diamond Weight (or Total Carat Weight) and display the total weight of all the diamonds.


How many Carats are in a Gram?


Carat is mass measurement. It's similar to using grams to weigh self-serve frozen yogurt and kilograms to measure people. Although it isn't used outside of the jewelry trade, it is an excellent system to deal with the smaller scale of lightweight gemstones.


A carat equals 0.2 grams. So a 1 gram diamond would have 5 carats.


We believe 0.45ct is better than 0.9 mg. Do you agree?


A quick reminder: Carat weight is always calculated using the metric system. It is not possible to use the imperial system.


What is the size of a 1 Carat Diamond?


One common misconception about diamonds is that their carat weight corresponds to the size of the diamond. Although this is true in some cases, it is not valid.


Round brilliant-cut diamonds must be cut according to the same standards as any other shape. A round diamond should be approximately 6.5mm in size if cut correctly. Sometimes a poorly cut diamond might be deeper than it should. A 1-carat diamond's diameter can drop to 5.8mm in these cases.


There are many fancy-cut diamonds available that cause variation, including Ovals and Pears, as well as Marquise Emerald-cuts. Unfortunately, this means it's like figuring out how many liters are needed to fill a swimming pool when you know only the length and width.


How do Carats work?


Now you know everything about carats and identify the various carat types. In addition, you can now read descriptions of jewelers like a pro if you understand the differences and what each one means.


We recommend 18ct gold as a choice for a wedding and engagement ring. The higher content of gold gives it some of the same properties we value in gold. On the other hand, 9ct gold costs half as much, but it tends to crack easily.


The choice of a diamond carat is entirely up to you! Consider your budget and taste when weighing diamonds. However, the carat is indicative of the weight but not necessarily the diamond's spread. Always inspect diamonds in-person to ensure they look as stunning as you would expect.


Fast facts about diamond carat


The carat will impact the other 4Cs (cut, clarity, color). It would be best to prioritize this when looking for a diamond that fits your budget. A higher color grade will make the diamond jewelry more visible. If you desire a bright, clear stone, you should choose a higher clarity level.


One carat is the most common size for engagement rings. Unfortunately, it isn't easy to visually distinguish between diamonds with varying carat weights of 5-10 percent. For example, a 0.95ct diamond and a 1ct diamond are almost indistinguishable.


Fast facts about gold karat


Gold is bright yellow in its purest form, 24 karats. In contrast, gold alloy is a mixture of pure gold and other metals. This gives the metal strength and color. The karat of gold will drop the more metals you mix with it.


Even if you are using the same color, a difference in the gold karat can dramatically alter your ring's appearance. For example, a 14-karat rose gold ring will look different from an 18-karat rose gold ring.


If you need any more information on karat vs. carat, we can help you out at AU Precious Metal Solutions.