What is Diamond Equivalent Weight?
Diamond Equivalent Weight, denoted as “DEW',' is used to indicate a gemstone's weight compared to a diamond of similar size, given gemstones, like moissanite, have a different density than diamonds. For example, a 1.00 carat round diamond (6.5 mm), and a moissanite of the exact same size only weighs approximately 0.88 carats. Using Diamond Equivalent Weight, this particular stone would be listed as 1.00 CT DEW.
Diamond Equivalent Weight (DEW) can be expressed in decimals or fractions. When expressed as a fraction for engagement ring center stones, the approximate decimal equivalents are as follows:
ROUND:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.50 | 5.00 |
| 1 CT DEW | 1.00 | 6.50 |
| 1 1/2 CT DEW | 1.50 | 7.50 |
| 2 CT DEW | 1.90 | 8.00 |
| 2 1/2 CT DEW | 2.70 | 8.50 |
| 3 CT DEW | 3.10 | 9.00 |
OVAL:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.50 | 6.00 x 4.00 |
| 1 CT DEW | 0.90 | 7.00 x 5.00 |
| 1 1/2 CT DEW | 1.50 | 8.00 x 6.00 |
| 2 CT DEW | 2.10 | 9.00 x 7.00 |
| 2 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 3 CT DEW | 3.00 | 10.00 x 8.00 |
PRINCESS:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.60 | 4.50 |
| 1 CT DEW | 1.00 | 5.50 |
| 1 1/2 CT DEW | 1.50 | 6.50 |
| 2 CT DEW | 1.92 | 7.00 |
| 2 1/2 CT DEW | 2.10 | 7.50 |
| 3 CT DEW | 2.80 | 8.00 |
PEAR:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.43 | 6.00 x 4.00 |
| 1 CT DEW | 0.94 | 8.00 x 5.00 |
| 1 1/2 CT DEW | 1.50 | 9.00 x 6.00 |
| 2 CT DEW | 2.10 | 10.00 x 7.00 |
| 2 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 3 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
EMERALD:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.58 | 6.00 x 4.00 |
| 1 CT DEW | 1.01 | 7.00 x 5.00 |
| 1 1/2 CT DEW | 1.75 | 8.00 x 6.00 |
| 2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 2 1/2 CT DEW | 2.52 | 9.00 x 7.00 |
| 3 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
CUSHION:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 1 CT DEW | 1.10 | 6.00 |
| 1 1/2 CT DEW | 1.70 | 7.00 |
| 2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 2 1/2 CT DEW | 2.40 | 8.00 |
| 3 CT DEW | 3.10 | 9.00 |
RADIANT:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.50 | 6.00 x 4.00 |
| 1 CT DEW | 1.00 | 7.00 x 5.00 |
| 1 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 2 CT DEW | 2.00 | 8.00 x 6.00 |
| 2 1/2 CT DEW | 2.50 | 9.00 x 7.00 |
| 3 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
MARQUISE:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.50 | 8.00 x 4.00 |
| 1 CT DEW | 1.00 | 10.00 x 5.00 |
| 1 1/2 CT DEW | 1.50 | 12.00 x 6.00 |
| 2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 2 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 3 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
HEART:
| AVERAGE DIAMOND EQUIVALENT WEIGHT | ACTUAL DIAMOND EQUIVALENT WEIGHT | ACTUAL MILLIMETER MEASUREMENT |
| 1/2 CT DEW | 0.50 | 5.00 |
| 1 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 1 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 2 CT DEW | 2.00 | 8.00 |
| 2 1/2 CT DEW | NOT AVAILABLE | NOT AVAILABLE |
| 3 CT DEW | 3.00 | 9.00 |