Diamond District

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The Carat

What is a Carat and how is it important in selecting an article of jewelry or loose stone?

One of the ways with which to determine a diamond’s worth is the Carat weight. The Carat weight is one of the four C’s, four industry wide, universal characteristics that the NYC Diamond District uses to determine a diamond’s value. The value of a carat increases with the size of the diamond since larger diamonds are far rarer.

A Carat is a measurement unit equivalent to 200 milligrams and is usually expressed as either fractions or points. A carat is assigned 100 points so that it can then be thought of in terms of either points or percentages. A diamond that is 33 points would be a 1/3 carat, (One third of a Carat) or .33 Carats.

Check out these charts to see the different diamond shapes and their relative carat weights.

Total Carat Weight

When an article of jewelry has more than one stone, the carat weight of each is combined to give a Total Carat Weight.  Let’s say we have a ring with three diamonds in its setting, a larger diamond and two smaller diamonds. If the center stone is ½ carat or .50 and the other two stones are an equal weight of .25, or ¼ carat each, the ring has a total carat weight of 1 carat.

1/4 + 1/4 + 1/2 = 1    or    .25 + .25 + .50 = 1.00

Diamonds weights may vary slightly so do not be alarmed if you discover your diamond weighs slightly more or less than the weight specified. Because of the difficulty involved with such small weights and fine cuts, the Federal Trade Commission set up guidelines that the diamond industry must strictly adhere to involving diamond carat weights.

The total weight of 1/4 carat may range from 0.21 to 0.29 carats
The total weight of 1/3 carat may range from 0.30 to 0.36 carats
The total weight of 1/2 carat may range from 0.45 to 0.59 carats
The total weight of 3/4 carat may range from 0.70 to 0.84 carats
The total weight of 1 carat may range from 0.95 to 1.10 carats
The total weight of 1-1/4 carats may range from 1.20 to 1.29 carats
The total weight of 1-1/2 carats may range from 1.45 to 1.55 carats
The total weight of 2 carats may range from 1.95 to 2.05 carats

When choosing stones for your unique jewelry design settings, the NYC Diamond District will always use the higher or exact weight rather than the lower.

The Importance of Carat Weight and Size

The depth and diameter of a diamond will increase in relation to the size of the diamond carat, which is why a diamond that has a diameter of 7.5mm and weighing 1-carat does not appear to be twice the width of a 1/2 carat diamond that is 6mm in diameter.