WHAT IS DIAMOND CARAT WEIGHT?
Carat weight is a measure of a diamond’s weight, and a reflection of its size.
1 carat is equivalent to 200 milligrams. Because carat is a record of a diamond’s weight – not its size – two diamonds of slightly different sizes may have the same carat weight. A diamond’s size is also dependent on how evenly its weight is distributed, and the quality of its cut. Some diamonds are cut to maximize carat weight, resulting in less sparkle. A balance of quality in carat and cut is therefore recommended.
For the best value, look at diamonds slightly lighter than the carat weight you initially want. For example, instead of 1-carat diamonds, consider 0.98 and 0.99-carat diamonds. The difference in size will be negligible, but savings here can be significant.
Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams.
Each carat can be 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 more rare and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4Cs: Clarity, Color, and Cut.
It’s important to remember that a diamond’s value is determined using all of the 4Cs, not just carat weight.
How did the carat system start?
The modern carat system started with the carob seed. Early gem traders used the small, uniform seeds as counterweights in their balance scales. The carat is the same gram 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.
Carat weight is the easiest to understand of the 4Cs. A diamond’s weight is measured in carats. The carat is subdivided into 100 equal parts called ‘points.’ One point equals .01 carat or 1/100 carat. A one carat diamond equals 100 points. Carat weight is written in decimal numbers, but it is frequently expressed in fractions which are easier to understand. Diamond weight fractions are approximate and refer to ranges of weight. This chart from The Diamond Council of America® is a handy reference:
Diamond prices increase with carat weight because larger diamonds are less common and more desirable. However, two diamonds of equal carat weight can have dramatically different values depending on three other factors: Color, Clarity and Cut. In jewelry pieces with more than one diamond, the carats are described in terms of total carat weight (T.W.). This is the combined total weight of all the diamonds in the piece. Determining the carat weight that is right for you depends primarily on your budget and taste.