| |
For
centuries, diamonds have been measured by weight to
determine its value. This was done as far back as
500bce in the Middle East. In 1907, at the Fourth
General Conference on Weights and Measures, the metric
carat was adopted standardizing this measurement.
Currently a carat is defined as exactly 200mg
(0.007,055oz, 3.086 grains). A carat is further
divided into 100 points. One point equaling
0.01ct, 1% of one carat or 2mg.
For
example, 0.75 ct. = 75 points, 0.50 ct. = 50 points.
The bigger the diamond, the more it weighs, the higher
its carat weight.
The following chart shows the
approximate diameter of a round brilliant diamond
compared to its carat weight. A few famous
diamonds included for comparison.
|
Carats |
Example |
Size |
|
0.10ct |
 |
3.00mm |
|
0.25ct |
|
4.10mm |
|
0.50ct |
|
5.20mm |
|
0.75ct |
|
5.90mm |
|
1.00ct |
|
6.50mm |
|
1.50ct |
|
7.40mm |
|
2.00ct |
|
8.20mm |
|
2.50ct |
|
9.00mm |
|
3.00ct |
|
9.30mm |
|
5.00ct |
|
11.00mm |
|
10.00ct |
|
14.00mm |
|
15.00ct |
|
16.30mm |
|
27.64ct |
Heart of Eternity
 |
19.99mm H
20.01mm W
11.89mm D |
|
45.52ct |
The Hope Diamond
 |
25.60mm H
21.78mm W
12.00mm D |
|
530.20ct |
Cullinan I
a.k.a. The Star of Africa
 |
54mm H
44mm W
29mm D |
|
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