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Carat Weight

A carat is the standard unit of measurement used to weigh diamond and gemstones. One carat (1.00 ct) equals 200 milligrams, or 0.200 grams. You may also have heard jewelers talking about "points". In common jewelry parlance, when referring to a diamond weighing less than one carat, jewelers use points, just like pennies are used for prices lower than one dollar. A point equals 0.01 ct. So, for example, a 15 point diamond is the same as a 0.15 ct diamond.

As large diamonds are rare, they have a greater value per carat and the price of diamonds rises exponentially in relation to size. Accordingly, a one carat diamond with a certain color and clarity will be much more valuable than two separate half carat diamonds of the same quality. Due to higher demand, diamonds increase in value after they reach the half and full carat mark.

CARAT WEIGHT
Select a carat weight to view a representation of the diamond size (see ring in photo to left)
1/4     11/2
1/3 2
1/2 3
3/4 4
1 5

It is a common misconception that a half-carat diamond is half the size of a one-carat diamond. While a half-carat diamond is half the weight of a one-carat diamond, the size difference in Round stones is only 1.35mm. The average measurements for a half-carat diamond and a one-carat stone are 5.00mm and 6.35mm, respectively.

BUYER'S TIPS - Which carat weight should you choose?
  • The best carat weight for a diamond often depends on the desired style, the size of the ring finger, the size of your setting, and your budget.
  • While the size of the diamond significantly affects its price, it does not guarantee beauty. Before you buy a diamond, it is best to first make a decision about preferred quality and then choose the size of diamond that you can afford in that quality range.
  • Remember that diamonds appear larger on smaller fingers. A 1.50 ct diamond solitaire will look bigger on a size 4 finger compared to a size 8 finger.
  • If you prefer a 1.00 ct diamond but are limited by your budget, consider a 0.90 ct one. Size difference between 0.90 ct and 1.00 ct diamonds is only very slight — even imperceptible to the untrained eye. A well-crafted 0.90 ct will comparatively have more sparkle, fire and brilliance than a 1 ct one for the same price or even less. This same argument also applies to other diamonds of comparative size ratios.