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The Relationship Between Diamond Carat and Price

By Tom McCambridge
4 min read
The Relationship Between Diamond Carat and Price

As you shop for the perfect diamond engagement ring, one of the first things you'll consider is the diamond's carat weight. Carat weight is a measure of a diamond's weight, with one carat equaling 0.2 grams. But how does the carat weight impact the price of a diamond, and what should you know before making a purchase?

Carat weight is one of the four C's of diamond quality, along with cut, colour, and clarity. While all of these factors are important, carat weight can have a significant impact on a diamond's price. Typically, the larger the diamond, the more expensive it is.

Diamonds are priced per carat, so as the carat weight goes up, the price per carat increases as well. However, the price per carat does not increase linearly. As the carat weight increases, the price per carat also increases exponentially. This means that a one-carat diamond will be more expensive than two half-carat diamonds of the same quality because the larger diamond will have a higher price per carat.

It's important to keep in mind that carat weight is not the only factor that affects the diamond's value. The other three C's can also impact the quality and value of the diamond. For instance, a one-carat diamond with a lower colour or clarity grade may be less valuable than a smaller diamond with a higher colour or clarity grade.

When buying a diamond, it's crucial to consider your budget and priorities. If carat weight is a top priority, you may have to compromise on other factors such as colour or clarity to stay within your budget. However, if quality is more important than size, you may want to go for a smaller, higher quality diamond. If opting for a yellow or rose gold setting, you can go lower on the colour of the diamond as this will reflect the warmth of the metal anyway.

In addition to carat weight, the diamond's cut is also a crucial factor to consider. A well-cut diamond will reflect light better and appear more brilliant, making it more valuable and desirable. So while carat weight is an important factor, it's essential to consider the other three C's and the diamond's cut to ensure you're getting the best value for your money. 

Also, fancy cut diamonds (any other cut than round brilliant) are not graded for cut, but they still have a polish and symmetry grade. Hence, it’s very important to look at each stone individually. Some things to look out for: 

  • Oval cut diamonds can have a ‘bowtie effect’ where light escapes in the middle making this part of the diamond appear darker, with less reflection.
  • Cushion cut diamonds can have a crushed ice effect, something that can be desirable and means that the reflections inside the diamond are very small and very reflective, making it sparkle more.

The carat weight of a diamond is a significant factor that impacts the diamond's value and price. Nevertheless, it's important to consider the other three C's and the diamond's cut to ensure that you're getting the best quality and value for your money. When buying a diamond, make sure to ask about the four C's and the diamond's cut to make an informed decision.

Although not mentioned in the four C’s, fluorescence is also a key factor to consider when searching for a diamond. Generally speaking, fluorescent diamonds cost slightly less, because a medium or strong fluorescence can (but doesn’t have to) make the diamond look sleepy. Faint fluorescence does not have that effect, but many people prefer to not opt for fluorescence at all. This comes down to personal preference; in some cases a blue fluorescence will make the colour of the diamond appear better (more colourless), as there is a natural fluorescence caused by daylight, therefore cancelling out the yellow in the diamond.

Spread is an important factor to consider when shopping for a diamond. A good spread will result in the diamond appearing larger than its carat weight - getting you more for your money. Spread is measured on the same scale as diameter, so a 0.5ct diamond with good spread may measure as much as 5.2mm, making it look closer to a 0.60ct diamond. It is important, however, that the depth of the diamond remains in proportion with its spread - otherwise you may end up with a stone that looks too shallow or too deep. A well-proportioned diamond will have both good spread and optimal depth, giving it maximum brilliance and sparkle.

At Holts Gems, we understand that every engagement ring is unique and personal to the wearer. That's why we offer a bespoke ring builder tool on our website, allowing you to design your own engagement ring with your desired style and diamond specifications, cut, and setting. With our guidance, you can create a one-of-a-kind ring that perfectly reflects your love story. 

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