Where diamond total weights are expressed by fractions, the approximate decimal equivalent is as follows:

1/20 ct = .04-.06

1/15 ct = .07-.08

1/12 ct = .08-.09

1/10 ct = .09-.11

1/8 ct = .12-.13

1/7 ct = .14-.17

1/6 ct = .16-.18

1/5 ct = .18-.21

1/4 ct = .22-.28

1/3 ct = .29-.35

3/8 ct = .36-.43

1/2 ct = .44-.53

5/8 ct = .54-.62

2/3 ct = .63-.69

3/4 ct = .70-.79

7/8 ct = .80-.88

1 ct = .95 – 1.05