CARAT WEIGHT:

A carat (ct.) is the unit of measurement specifically used to describe the weight of a diamond (or other gemstones). A single carat is divided into 100 points. For example: 0.33 carats is generally expressed as 33 points, or 1/3 of a carat. Because large diamonds are much rarer in nature than smaller ones, the diamond value increases exponentially for certain thresholds of diamond carat weights. A 1.00-carat diamond will cost more than twice as much as a 0.50-carat diamond of comparable quality.