One of the most useful tools a jeweller can have when designing jewellery is an idea of what different size rubies weigh.
The chart below is an easy way to reference what a ruby weighs in different sizes and shapes. This information together with other information in The Ruby Hub will then enable you to know more or less what carat size stone to look for and how that might affect your budget when costing a finished piece of jewellery.
A very useful tool in the jeweller's tool box.
The weights for ruby sizes are approximate. Gemstones of all types are cut to maximise the look and life of the stone, so tend to be a little less standardised. This chart is essentially meant as a guide.
 Round |
|
| Round (mm) | Weight (cts) |
| 1 | 0.006 |
| 1.5 | 0.017 |
| 2 | 0.04 |
| 2.5 | 0.08 |
| 3 | 0.15 |
| 3.5 | 0.22 |
| 4 | 0.34 |
| 4.5 | 0.45 |
| 5 | 0.66 |
| 5.5 | 0.83 |
| 6 | 1.09 |
| 6.5 | 1.36 |
| 7 | 1.64 |
| 7.5 | 2.12 |
| 8 | 2.50 |
 Oval |
|
| Oval (mm) | Weight (cts) |
| 5x3 | 0.29 |
| 6x4 | 0.59 |
| 7x5 | 1.06 |
| 8x6 | 1.65 |
| 9x7 | 2.36 |
| 10x8 | 3.50 |
| 11x9 | 4.90 |
| 12x10 | 6.80 |
 Pear |
|
| Pear (mm) | Weight (cts) |
| 5x3 | 0.25 |
| 6x4 | 0.53 |
| 7x5 | 0.87 |
| 8x5 | 1.02 |
| 9x6 | 1.62 |
| 10x7 | 2.43 |
| 11x9 | 4.18 |
 Octagon |
|
| Octagon (mm) | Weight (cts) |
| 5x3 | 0.35 |
| 6x4 | 0.70 |
| 7x5 | 1.30 |
| 8x6 | 2.00 |
| 9x7 | 3.10 |
| 10x8 | 4.40 |
| 11x9 | 6.18 |
| 12x10 | 8.30 |
 Square |
|
| Square (mm) | Weight (cts) |
| 2x2 | 0.06 |
| 3x3 | 0.22 |
| 4x4 | 0.56 |
| 5x5 | 0.80 |
 Marquise |
|
| Marquise (mm) | Weight (cts) |
| 4x2 | 0.12 |
| 4.5x2.5 | 0.15 |
| 5x2.5 | 0.20 |
| 5x3 | 0.24 |
| 6x3 | 0.29 |
| 7x3.5 | 0.45 |
| 8x4 | 0.75 |
| 9x4.5 | 1.00 |
| 10x5 | 1.30 |
| 12x6 | 2.06 |
 Heart |
|
| Heart (mm) | Weight (cts) |
| 3x3 | 0.15 |
| 4x4 | 0.32 |
| 5x5 | 0.65 |
| 6x6 | 1.00 |
| 7x7 | 1.60 |
| 8x8 | 2.00 |
| 9x9 | 3.42 |
 Cushion |
|
| Cushion (mm) | Weight (cts) |
| 3x3 | 0.12 |
| 4x4 | 0.32 |
| 5x5 | 0.65 |
| 6x6 | 0.95 |
| 7x7 | 1.60 |
| 8x8 | 2.00 |
| 9x9 | 3.42 |
More aboutRubies
Often referred to as the king of gems, Rubies radiate warmth and vitality and when worn represents love, health and wisdom. Ruby, the July Birthstone, has been a very popular gemstone since antiquity, and is one of the most historically significant coloured gemstones. The ruby has now entered a new era of popularity with many people opting for this romantic stone as an alternative to diamonds in their wedding jewellery.
Due to their symbolism of strength and vitality, rubies are also a popular gemstone to wear for men.