Last updated on February 14, 2020
Let’s suppose you are about to buy a diamond of 1-carat weight and ask the salesperson to show you several stones. Do you know that those 1-carat diamonds you are looking at may not be exactly 1 carat? Let’s see what’s behind diamond standard carat weights and why this is a common thing in the industry.
Advertised Carats are Usually Approximate
We are all used to standard diamond values such as 0.5, 0.75, 1 carat etc. However, in reality, it’s a rare thing when a diamond weight corresponds exactly to one of these numbers.
A 1-carat diamond shown to you may actually be 0.97 or 1.05. That’s why you should never expect two diamonds with the same carat tag to have perfectly identical weight.
It’s perfectly normal for diamond carat weight not to match the exact standard number. The advertised carat weights are usually mentioned in approximate numbers.
There is nothing to worry about. This is a normal practice and jewellery shops don’t try to hide anything from you; you can always find the exact carat weight of a diamond in its certificate (a grading report).
Why Not Cut Diamonds in Exact Carat Weights?
Often it’s not possible to cut a diamond so that it matches an exact standard value.
For example, a stone’s carat weight may be intentionally reduced to cut out segments that contain a lot of flaws and improve the diamond’s clarity. It’s also a common practice to cut out some rough to create a more proportional cut that maximizes the brilliance and sparkle.
However, diamond cutters also try to minimize the waste of the rough. As a result, the finished stone will have a carat weight that will be close to standard values, but there will be some variation in most cases.
What is the Normal Carat Variation?
For advertised carat weight it’s totally normal to have variation within 0.06-0.08 carats.
For example, a 0.94-carat diamond may be advertised as a 1-carat stone. Or a diamond claimed to be 0.75 carats may actually be 0.8 carats.
Keep in mind that you can always ask the jeweller about the exact carat weight of the stone or check the value in the diamond’s grading report.
Is the Difference in Carat Weight Visible to the Naked Eye?
It all depends on the deviation. Of course, you will be able to see the difference between 0.75-carat and 1-carat diamonds. However, the deviation of 0.05 and 0.1 carats is hardly detectable.
For example, if you put a 0.95-carat diamond next to a 1-carat stone, it will be really hard to spot the difference. Not to say about spotting the difference when the diamond is worn.
Carat Weight Variations vs Prices
In-demand size diamonds such as 0.25ct, 0.5ct, 0.75ct, 1ct, 2ct etc. have higher prices than stones that are smaller just by few points.
For example, if you want to buy a 1-carat diamond then choose a stone that is 0.95 or 0.98 ct. No one will notice the actual difference but you can expect to pay much less for it.