DIAMOND CARAT RATING SCALE
Carat WEight
The simplest factor in determining the value of a diamond among the Four C's is its carat weight. This is because weight is the standard measure used for all precious gemstones, expressed in carats. One carat is equivalent to one-fifth of a gram or 1/142 of an ounce. This measurement can also be represented in points, where 100 points equals one carat. For instance, a diamond that weighs 0.75 carats can also be referred to as 75 points.
Before a diamond is set into jewelry, it is weighed with precision. As diamonds increase in size, their per carat price typically rises in an exponential manner. To illustrate, a two-carat diamond will be more expensive than twice the price of a one-carat diamond of the same quality.