Carat Weight, Diamond Size, Four C's, four cs, 4 c's, 4cs, cut, clarity, color, grading, grades, chart

The size of a diamond is defined by carats, which is an expression of weight.  One carat weighs 1/5 of a gram, and is divided into 100 points, like pennies to a dollar.  The larger the diamond, the more rare and costly.  However, depending on color, clarity, and cut two diamonds of the same carat weight can vary widely in their value.