Education for Carat Weight - DiamondHouseAZ.com

In case you were wondering - size does matter.  Besides the shape of a diamond, carat weight is by far the most important diamond characteristic to most women.  Gold and platinum are weighed in grams.  Diamonds are weighed in carats.  The bigger the diamond, the rarer it is, and therefore, the more expensive it is.  However, carat weight does not necessarily denote a diamond’s diameter.  For instance, a 1 carat round brilliant cut diamond may weigh 1 carat and measure 6.5 mm at its length and width, while another 1 carat round brilliant cut can measure 6.0 mm (perhaps because more of the weight of the diamond is in its depth).  Therefore, it is possible to pay the same amount of money because a diamond weighs the same as another even though it looks much smaller to the eye.  This is why it is important to pay attention not only to the carat weight of a diamond but its physical diameter as well.  The diameter of your diamond can be found toward the top of the diamond grading report (certificate).  The measurements of a diamond will be given to you in the order of length, width and depth (all measured in millimeters).

6.50 – 6.46 x 4.00 mm

Diamonds are priced exponentially higher the heavier they are.  Even though a diamond has the same shape, cut, color and clarity as another, because of the difference in carat weight, they are priced/valued dramatically different. 

0.50ct – 0.69ct   

0.70ct – 0.89ct

0.90ct – 0.99ct

1.00ct – 1.49ct

1.50ct – 1.99ct

2.00ct – 2.99ct

3.00ct – 3.99ct

4.00ct – 4.99ct

5.00ct – 5.99ct

10.00ct – 10.99ct

Also important to note is the difference between a straight size and an oversize.  Each weight group has a straight size and an oversize.  For example, in the weight category of 1.00ct – 1.49ct, 1.00cts – 1.19cts are considered straight sizes while 1.20cts – 1.49cts are termed oversize.  In the 2.00ct – 2.99ct weight group, 2.50cts and heavier are referred to as oversized.  Oversize diamonds are typically valued at a premium of 5% to 10% over straight sizes. 

1.00ct Round Brilliant G SI1              $5,700.00 per carat     $5,700.00 net