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.

Anne M.
Highly recommend. I had an old mine cut diamond that was a family heirloom remade into an engagement ring, and I took it to a jeweler who completely messed it up and set the diamond wrong and it fell... out. They had also resized the band incorrectly. David is an expert. We went to him and he reset the diamond beautifully, fixed the band, and it’s amazing. Also, because the diamond is so old and so unique we couldn’t find a wedding band that went with it correctly. David had a wedding band for us custom made, that looks AMAZING. Everything was done in a reasonable amount of time, for a reasonable price, with great expertise and craftsmanship. Go to David!!read more
Angela
David Stern did an amazing job sizing my mother’s engagement ring. I needed the ring size from 5 to 9 to give to my sister in-law. When I picked the ring up it looked like a brand new ring and looks... better than it did when I brought it in. His work is excellent, fast, and very reasonably priced.read more
Ginny L.
David Stern was so accommodating, friendly, and professional! I only went in for a small service, (changing my engagement ring into a necklace) Not only did he do an amazing job, he treated me as... though I was buying the most expensive item in the store. 🙂 I highly recommend David Stern Jewelers.read more