This style of diamond is often referred to as an Asscher cut diamond. In this light, we are looking to see which diamond has the brighter, whiter areas on the diamond and so which shows the best light return.
The stone on the left is a typical square emerald. It is suffering from light leakage in the table of the diamond, making it a little glassy, which you can see by the lack of light return. The stone on the right is absolutely gorgeous with excellent light return. This is what you should be aiming for in Asscher cut diamond.
It is apparent is the lack of fire in the table of the diamond on the left. This is caused by the facets not being correctly positioned causing light leakage in the stone. In comparison, the diamond on the right is looking absolutely stunning. This is also the amount of fire you should be aiming for stone cut to give the best optics.
In terms of their proportions, both diamonds have a depth percentage of 68%. The table on the size right stone is 62% whilst the left hand stone is 58%. You might expect the stone with the smaller table to generate more fire from the crown, but as you can see this is not the case.
This is why when we select our Asscher cut diamonds, we find it is essential to hand pick each one for perfect optics to ensure right level of brightness and fire in the diamond. This way we can weed out diamonds like the stone on the left, which sound rather good based on the information in the GIA lab report, but in practice disappoint when you inspect them with your eyes.
