A metric carat is equal to 0.2 Grams or 200 Milligrams. A carat is divided into 100 points:

1/4 ct. = 25 points = .25 ct.

1/3 ct. = 33 points = .33 ct.

1/2 ct. = 50 points = .50 ct.

3/4 ct. = 75 points = .75 ct.

As a diamond's weight increases, the price per carat increases to reflect the fact that larger diamonds are more rare.