In a previous article, I briefly touched the aspect of perception in our judgement of numbers. I made the case, that since most diamond professionals first gather their knowledge with round brilliants, that they automatically apply rules for rounds to fancy shapes. This is also true with numbers.
In this article, I will give you some examples how numbers and perception can interact.
Example 1. An AGS-0 princess-cut, Crafted by Infinity
Here are the basic measurements for this stone, as mentioned on the AGS-report:
| Weight: | 1.257 Cts. |
| Measurements: | 5.78 x 5.78 x 4.60 mm. |
| Total depth: | 79.6% |
| Table %: | 59.7% |
| Crown angle: | 32.8° |
| Crown height: | 11.2% |
| Pavilion angle: | 42.7° |
| Pavilion depth: | 64.9% |
| Girdle | 2.7% to 3.8% |
| Culet: | Pointed |
Example 2. The same diamond, but with the measurement noted in the same way as for a round brilliant
In a round brilliant, all percentages are calculated as a percentage of the average diameter, while in fancy shapes, they are calculated as a percentage of the smallest diameter. Let us now show you the measurement of the same diamond, but this time according to the normal notation of a round brilliant.
| Weight: | 1.257 Cts. |
| Measurements: | 8.17 x 5.78 x 4.60 mm. |
| Total depth: | 65.9% |
| Table %: | 49.4% |
| Crown angle: | 32.8° |
| Crown height: | 9.3% |
| Pavilion angle: | 42.7° |
| Pavilion depth: | 53.8% |
| Girdle | 2.2% to 3.1% |
| Culet: | Pointed |
Just looking at the figures, these measurements look a lot better than in the first example. First, it clearly shows the diameter from point-to-point being 8.17 mm. Also, the total depth-notation went from 79.6% to 65.9%, which sounds a lot better, especially since we are used to depths around 60% in round brilliants.