Carat Weight vs. Measurements

Let’s talk numbers.

Diamonds are priced based on a unit of measurements known as ‘carats.’ Despite what most people believe, the ‘carat’ of a diamond refers to its weight and not its actual measurements.

What does this mean?

Measuring a Carat Weight

In simple terms, ‘one carat’ is equal to 200 milligrams or 0.2 grams. This is the only constant. The actual millimetre measurements of the diamond can vary. Hence, a 1 carat round brilliant diamond could have a face-up diameter ranging anywhere between 6.15mm and 6.60mm. The difference between the diamonds would be their depth – more on this shortly.

It’s important to remember that once the diamond is set into any type of jewellery – ring, earring, or pendant - only the face up measurements are visible. With this in mind, let’s look at the two Round Brilliant diamond options below. They are identical in quality – both of them have been certified by the Gemological Institute of America [GIA] as a ‘D’ colour grade and a ‘VS1’ clarity.


Depth of a Diamond

The difference between the two diamonds above, are the measurements of the depth. They are 3.78 and 4.02 mm respectively. The depth of a diamond refers to the millimetre measurement from the diamond's table (top) to the culet (bottom). Keeping in mind that the depth of the diamond has no effect on the face up appearance, we would be spending an extra £2,400 for a diamond simply because it is a ‘one carat.’ The degree of the price difference will vary based on the quality of the diamond, however, rest assured that your gemologist will be able to source a 0.90 carat diamond with above average measurements.

If a Round Brilliant Diamond is not your style, the same holds true for all diamond shapes! Whether you’re considering an Oval, Emerald, Cushion, or even a Princess Cut Diamond, focussing on the measurements (i.e. length and width) instead of the carat weight should always be a key factor. Even if a slight premium is charged for such diamonds, the value in purchasing them would be extraordinary. Flaunt that ‘one carat’ diamond – it’ll be our little secret!

Our Diamond Concierge Service is completely free. There's no obligation to purchase from us. We're here to shine some light - and will always do so unbiasedly. Let us help you find your perfect diamond.

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