5C’s of Diamond Buying – Carat

So, on to the next C … Carat.

A carat is a unit of measurement used for the weight of gemstones.  This is not to be confused with karatKarat with a “k” denotes the purity of gold.  For example, 18k gold means the piece in question has 18 parts pure gold out of 24 parts total.  Pure gold is 24k.

The term carat is derived from the carob tree alluding to an ancient practice of weighing gold and gemstones against the seeds of the tree by people in the Middle East. The system was eventually standardized, and one carat was fixed at 0.2 grams.

The most important thing to remember about carat is that it refers to weight – not size.

So, what does this actually mean for you?  It means, just because a diamond has a larger carat weight, it doesn’t necessarily mean it will look bigger.  Why?  Because the weight of the stone could be concentrated on the pavilion (bottom) of the diamond … the part you don’t see once the stone is set.

Some poorly cut diamonds can be “bottom heavy” meaning they’re cut too deep resulting in the stone not only looking dark and dull (due to trapped light within the stone) but also this stone will look smaller face-up compared to one that is well cut of the same carat weight.  See my post on cut to learn more.

Some styles of cutting naturally have a deeper pavilion.  For example, Asscher cut, Old Mine cut and even Emerald cut all have deeper pavilions.  So, a one carat Emerald cut diamond will look smaller than a one carat round brilliant face-up because the Emerald cut diamond has more weight on the bottom of the stone due to the proportions of the cutting style.


Diamond prices increase significantly at certain “marker” weights.  For example, a 1.00 ct. diamond will be priced much much higher than a 0.93 cts. diamond.  I’m talking significant savings here.  If you can, it is always smart to look for diamonds that are just under these “marker” weights … you can get a fantastic deal here if you know what you’re looking for.  See chart below to compare size and weight in round brilliant cuts.

To the untrained eye, the difference in size between a 1.00 ct. diamond and a 0.93 ct. diamond is hard to see, so essentially, you can get the “look” of a 1.00 ct. stone for 3/4 of the price!

However, you should be careful about the cut and proportions of these “underweight” diamonds, often times, they may not be cut well resulting in a not-so-sparkly diamond.

Also remember that, just because a stone is bigger, doesn’t mean it’s “better”.  Once again, all 4C’s contribute to the beauty and ultimately price of a diamond.

If size is more important to you than a whiter, cleaner stone, then by all means go for the stone with the biggest carat.  If you prefer a better quality stone in terms of color, clarity and cut, you may have to opt for a smaller size diamond in order not to bust your budget!

Above is a 1.00 ct. stone on a size 5 finger.  See chart below for finger coverage (in %) based on carat weight and finger size!  Brilliant.

It is so important to see as many stones as you can to compare and decide which C is most important to you.  You may decide that because carat weight (and thus size) is something that is noticeable right away compared with a microscopic factor like clarity, that of the 4C’s, carat is most important to you.  Or vice versa.

Happy Shopping!

(images via Orionz Jewels, michelleelaineweddings.com, weddingbee.com, biolib.de)


One thought on “5C’s of Diamond Buying – Carat

  1. Pingback: How To Buy An Engagement Ring | Siam Gem Palace

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