How to Buy a Diamond - The Four C's CUT How a diamond
has been cut, polished, and to what proportions and symmetry, are of utmost
importance since these factors determine the life, brilliance and dispersion of
the diamond. If these cutting factors fall below standard, the appearance of the
diamond will be adversely affected.
 CARAT The weight or
size of a diamond is measured in carats. A carat is 0.2 grams and there are 100
points (or 200 milligrams) per carat. With an accuracy of 1/100,000 ct, the gem
laboratory scales provide a highly precise diamond weight and this weight is
specified on the Diamond Report to two decimal points. | 
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| Carat | 0.05 | 0.10 | 0.20 | 0.25 | 0.30 | 0.40 | 0.50 | 0.70 | w m/ m | 2.5 | 3.0 | 3.8 | 4.1 | 4.5 | 4.8 | 5.2 | 5.8 | h m/ m | 1.5 | 1.8 | 2.3 | 2.5 | 2.7 | 3.0 | 3.1 | 3.5 | | 
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| Carat | 0.90 | 1.00 | 1.25 | 1.50 | 1.75 | 2.00 | 2.50 | 3.00 | w m/ m | 6.3 | 6.5 | 6.9 | 7.4 | 7.8 | 8.2 | 8.8 | 9.4 | h m/ m | 3.8 | 3.9 | 4.3 | 4.5 | 4.7 | 4.9 | 5.3 | 5.6 |
CLARITY In order to
grade the clarity of a diamond, it is necessary to observe the number and nature
of any internal characteristics in the stone as well as their size and position.
This analysis is carried out using the GIA scope and a loupe 10x under the
experienced eye of laboratory gemologists. A diamond is said to be
"Internally Flawless" when it presents no internal defects under 10x
magnification. 
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| Internally Flawless | Very Very Slightly included | Very Slightly included | Free from internal blemishes visible under 10x magnification (small external details tolerated). | Inclusions and/or external blemishes very difficult to locate under 10x magnification. | Inclusions and external blemishes difficult to locate under 10x magnification. |
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| Slightly included | Imperfect | Imperfect | Imperfect | Inclusions and external blemishes easy to locate under 10x magnification. | Inclusions and external blemishes hard to locate with naked eye. | Inclusions and external blemishes easy to locate with naked eye. | Heavy inclusions located with |
COLOR Most diamonds of
gem quality vary in shade from colorless to yellow. To determine the correct
color, all submitted diamonds are compared to an internationally accepted master
set of stones, the color of which ranges from D, or colorless (the most
sought-after) to Z, the darkest. Other colors occur in diamonds such as
brown, orange, pink, blue, etc. The most intense of these shades are determined
as "Fancy" colors. | | GIA or EGL | | Description | | 
| Colorless | D | | Exceptional White+ | | E | Exceptional White | | F | | Rare White+ | | 
| Near Colorless | G | Rare White | | H | | White | | I | | Slightly Tinted White | | J | | 
| Faint Yellow | K | | Tinted White | | L | | M | | Tinted | | | 
| Very Light Yellow | N | | O | | P | | Q | | R | | 
| Light Yellow | S | | | T | | Yellow | U | | V | |
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