Diamond Carat Weight

To put it simply, diamond carat weight measures how much a diamond weighs. 

A metric “carat” is defined as 200 milligrams. Each carat is subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place. A jeweler may describe the weight of a diamond below one carat by its ‘points’ alone. For instance, the jeweler may refer to a diamond that weighs 0.25 carats as a ‘twenty-five pointer.’Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as ‘one point oh eight carats.

All else being equal, diamond price increases with diamond carat weight because larger diamonds are rarer and more desirable. However, two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4CsColorClarity, and Cut.

While now you know what carat means, it’s also important to remember that a diamond’s value is determined using all of the 4Cs, and not just carat weight.

How did the carat system start?

In order to understand what a diamond carat measures, it would help to know the origins of the modern carat system. Carat weight started with the carob seed, when early gem traders used the small, uniform seeds as counterweights in their balance scales. Today, the carat is the same milligram weight in every corner of the world.

What are “magic sizes”?

Some weights are considered “magic sizes” – half carat, three-quarter carat, and carat. Visually, there’s little difference between a 0.99 carat diamond and one that weighs a full carat. But the price differences between the two can be significant.

Elise R.
David Stern and his staff are very professional. The owner is a jeweler and appraiser as well as designer. He is an old school class act. Very respectful, funny and personable. I highly recommend... this store for all of your jewelry needs including repair, designing something unique, estate pieces.read more
Moriah W.
David did an amazing job cleaning and plating my jewelry. He cleaned it so well I didn’t even recognize it! Excited to go back in the future. He is very knowledgeable and trustworthy. I 10/10... recommend taking your business to David Stern Jewelers!read more
Kindra J.
Mr. Stern was very knowledgeable, kind, honest, and informative. He’ll let you look at your jewelry with his tools to get the full picture of his appraisal. He explains the process of selling jewelry... and is very thorough. Although I did not sell my piece of jewelry as it was, he offered to transform it into another piece of jewelry which was a lovely idea. I definitely will return.read more