Diamond Grading Guide
Carat
The weight of a diamond is expressed in carats. 1ct =0.2 gram
| 0.05 | 0.10 | 0.15 | 0.20 | 0.25 |
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| 0.5 | 0.75 | 1.0 | 1.25 | 1.50 |
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| 1.75 | 2.0 | 2.5 | 3.0 | 4.0 |
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| 5.0 | 7.0 | |||
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Please note: images not to scale
Clarity
A diamond is called "loupe clean" if, after examination by an experienced grader with a loupe 10x under normal light conditions, it has been found free of internal characteristics. The other clarity grades are determined by the size, position, brightness and number of internal characteristics. External characteristics and structure phenomena can be mentioned under "identification marks" or "comments". The lowest clarity grades on the scale ( indicated by P for piqué) refer to inclusions that can be seen by an experienced grader with the naked eye.
| LC | VVS1 | VVS2 | VS1 | VS2 |
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| SI1 | SI2 | P1 | P2 | P3 |
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Colour
Colour is graded by comparison to master stones under standardised artificial light, equivalent to Northern Daylight.
| D | E | F | G | H |
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| exec white + | exec. white | rare white + | rare white | white |
| I | J | K | L | M |
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| slightly tinted white | tinted white | tinted...... | ||
| N-O | P-R | S-Z | ||
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| tinted colour | ||||
Cut
Cut to the ideal proportions in terms of angles and ratios and with the finest possible finish, a diamond can be coaxed to its maximum intrinsic radiance. On a HRD certificate, the description of the cut is split in to a separate description of the proportions (angles of inclination and proportional relations between the various parts of the stone) and finish, which is mainly concerned with symmetry deviations and the positioning of the facets.
Shape
Some common diamond shapes
| Round Brilliant | Emerald | Heart | Marquise | Oval |
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| Pear | Princess | |||
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