A carat weight is one-fifth of a gram or 200 milligrams. Carats can also be referred to as points.
|0.005 ct||half point|
|0.05 ct||five points|
|0.25 ct||twenty-five points or quarter carat|
|0.50 ct||fifty points or half carat|
|1.65 ct||one point sixty five carats or one sixty-five|
When shopping for diamonds, think in terms of the per-carat cost instead of the total cost of the stone. To calculate the per-carat cost, use the following formula:
|Per-Carat Cost =||stone cost__|
With this formula, you'll be able to decide which ring is a better buy.
Normally, the size of a diamond is synonymous with the carat weight since diamonds with the same carat weight tend to have the same dimensions. As diamonds increase in weight, it's not accurate to say that heavier diamonds of equal carat weight are equal in size.
For these reasons, it's best to compare gemstones according to their specific gravity. The specific gravity is the ratio of a gem's weight to the weight of an equal volume of water at four degrees Celsius.
For example, the specific gravity of a diamond is 3.52 while that of a cubic zirconia is 5.80. A one-carat cubic zirconia is smaller than a one-carat diamond because the cubic zirconia has a higher density.