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Diamond Carat




Diamond Carat Weight

A carat, not carrot, is the unit of measurement used to determine the weight of a diamond. A single diamond carat is equal to the weight of 200 milligrams, or .2 grams. Carat is a word derived from carob seeds, which were used to balance scales in ancient times. Yes diamond seekers; this is the same carob seed we get our divine chocolate from.


These scrumptious little seeds are so uniform and symmetrical in shape and weight that even today's sophisticated and complicated devices cannot detect more than three one-thousandths of a difference between them. That's why they are used as the measuring rod for determining diamond carat weight.

Diamonds are described two different ways in regards to the diamond carat. An abbreviation of “ct” is used to describe the weight of a single diamond stone while an abbreviation of “ct TW” is used when describing the total weight of an entire piece of jewelry - when it has more than one stone in place.


It's important to recognize that two stones may have the exact same carats, meaning they have the same weight measurement, and yet they are completely different in size and appearance. This is due to the actual density of the gemstone. The more dense a stone is, the more weight they will have, and sometimes a smaller stone can actually weigh more than a larger stone because of density.

Diamond Carat facts:


·   A carat is equal to 200 milligrams and there are 142 carats to an ounce.

·   There are 100 points to a carat

·   A one-carat diamond of the highest clarity and color can easily cost as much as a diamond almost twice its size with lower color and clarity

·   The most popular diamond sizes are: half carat, three-quarter carat and a carat.

·   There’s very little visual difference between a 0.98 ct. diamond and one that weighs a full carat. Yet, the price difference between the two can be significant.

·   A melee (meh-lee) is less than 0.15ct., and is often grouped together in clusters and/or set around larger stones


Here’s your test question, “What would a fifty-point diamond weigh?” Answer: half a carat!  


How a Diamond’s Weight Affects its Value

When selecting your diamond ring, you can choose between a single, solitaire style setting (a single diamond on the ring) and a setting that has multiple, smaller stones to make up the ring.


The value of a solitaire one diamond carat will actually be more than if you buy a ring that has two diamonds that add up to one carat or greater. Larger sized diamonds are more rarely found when mining diamonds, making them more valuable and expensive than purchasing the same amount of diamond carats in smaller stones.


Selecting Diamond Carat

How do you determine the size of diamond to buy? Do you want a diamond carat of one, or two, or do you want a ring with multiple, smaller stones? The answer depends primarily on your budget, as well as the person who’ll be wearing the ring. 


A diamond will look larger on a slender finger, so keep that in mind if the recipient of the ring has thin hands. The actual diamond carat measurement is probably not as much of a concern as the appearance, shape, and setting of the ring.


Particularly because a one carat diamond ring will not look half the size of a two carat diamond ring. It's far more important to select a ring that is pleasing to look at than to buy one with the most carats you can afford.


Determine how much money you have to spend, and then decide on the cut of the diamond. Once you have these two pieces of information narrowed down, you can start browsing the diamonds in your price range, in the style you want, and find out what diamond carat you are in the market to buy.

    Most Popular Diamond Weights



Fifth of a carat

0.20 ct.

Quarter carat

0.25 ct.

Third of a carat

0.33 ct.

Half carat

0.50 ct.

Three-quarter carat

0.75 ct.


1.00 ct.





Go back to: The Buying Diamonds Guide.

Go back to: The 4 C's of Diamonds

Source: Vicente Ross,




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