4C's : Carat Weight
A carat is the unit of measurement which the jewelry industry uses to weigh a diamond. One carat is equal to .20 grams. Often diamond weight is declared in points. One carat is equal to 100 points. Thus, a .75 carat diamond is equivalent to 75 points.
Do not buy into the belief that the larger the carat weight, the more valuable the diamond. While this can be true, it is not necessarily so. Keep in mind that retail and wholesale diamond dealers take into account a stone's color, clarity, and cut, as well as carat weight when pricing a diamond and often their pricing is subjective. For that reason, it is important for every potential buyer to prioritize each of the aforementioned characteristics when considering a stone. Remember that choosing diamonds is not an exact science.
Note: Use this chart as a relative guide only.
Diamonds On Web Best Value: Carat
When selecting the best carat weight, take into consideration her taste & style, her finger size, the type of band or setting, and your budget.