Minimum total carat weight is the combined minimum carat weight of all the diamonds in a piece of jewelry or the minimum of the weight of a single stone. The actual diamond you purchase may weigh slightly more or less than the fractional weight or decimal specified. Money is saved if a 6.5mm 1.0ct diamond weighs .96ct – but it’s the same millimeters as the 1.0ct but weighs slightly less, but not noticeable in size. The Federal Trade Commission has strict guidelines about the range of carat weight that a fraction can represent. The chart below outlines acceptable ranges for carat weights expressed as fractions.
1/4 carat total weight of 0.23 to 0.28 carats
1/3 carat total weight of 0.29 to 0.36 carats
1/2 carat total weight of 0.46 to 0.55 carats
3/4 carat total weight of 0.70 to 0.79 carats
1.0-carat total weight of 0.96 to 1.05 carats
1 1/2 carats total weight of 1.45 to 1.53 carats
2.0 carats total weight of 1.96 to 2.04 carats