Common goods are weighed
by the kilo, ounce, pound, or ton.
Luckily there's nothing common about diamonds.

Diamond weight is measured with more precision using metric carats, abbreviated "cts". One metric carat is 1/5 of a gram, just over 0.007 of an ounce. Whereas 1oz. contains almost 142 carats.

4.4

.33

5.2

.50

6.5

1.00

7.4

1.50

8.2

2.00

8.5

2.50

MM

Carat

Pricing diamonds per carat is how most wholesalers quote diamond prices. For example, one might say he has a 1.25-carat diamond for $3000.00 per carat. To find the total cost, multiply the per-carat price by the weight. In this case, $3000.00 X 1.25ct = $3750.00.

The degree of rarity in a diamond is reflected in its per-carat price.