Just read drk14's post - thank you....that adds a little bit more to my understanding...so some depth is needed, especially above the girdle, for better performance...but too much depth means the stone will face up small....i can see very clearly that the following selection from Gypsy performs better, but i think im beginning to understand why
http://www.jamesallen.com/loose-diamonds/cushion-cut/1.01-carat-f-color-vs2-clarity-sku-305967
http://www.jamesallen.com/loose-diamonds/cushion-cut/1.01-carat-f-color-vs2-clarity-sku-305967