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Other Links | 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. | Reflection | Refraction | Dispersion |  |  |  | A) When a ray of light touches the surface of a diamond, part of the light is reflected back, this is external reflection. | B) The rest of the ray penetrates the stone and is then reflected toward the center of the diamond. This is known as refraction. | C) The ray of light is reflected to the surface, where it is seen as the colors of the spectrum. This is known as dispersion. |
Execution of the design, the precision of the cutting details and the quality of the polish are collectively called the finish. |  |
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| CARAT The weight or size of a diamond is measured in carats (ct.). 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 IGI scales provide a highly precise diamond weight and this weight is specified on the Diamond Report to two decimal points.
|  |  |  |  |  |  |  |  | | Carat | 0.05 | 0.10 | 0.20 | 0.25 | 0.30 | 0.40 | 0.50 | 0.70 | | Øm/ 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 | |  |  |  |  |  |  |  |  | | Carat | 0.90 | 1.00 | 1.25 | 1.50 | 1.75 | 2.00 | 2.50 | 3.00 | | Øm/ 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 |
| CLARITYIn 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 Diamond Clarity Grading is carried out using the IGI 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.
 |  |  | | 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. |
 |  |  |  | | 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 very easy to locate with the naked eye. |
| COLOURMost 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 yellowest.
Other colors occur in diamonds such as brown, orange, pink, blue, etc. The most intense of these shades are determined as "Fancy" colors and referenced on the IGI Diamond Report.
| | IGI | CIBJO | IDC |  | Colorless | D | Blanc Exceptionnel | Exceptional White+ | | E | Exceptional White | | F | Extra Blanc | Rare White+ |  | Near Colorless | G | Rare White | | H | Blanc | White | | I | Blanc Nuancé | Slightly Tinted White | | J |  | Faint Yellow | K | Blanc Légèrement Teinté | Tinted White | | L | | M | Teinté | Tinted |  | Very Light Yellow | N | | O | | P | | Q | | R |  | Light Yellow | S | | T | | Yellow | U | | V |
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