Love this site! I’m looking for an eye clean cushion cut diamond in the 1.2-1.5 carat f/g/h range, but the efficient frontier tool won’t let me filter on cut quality. What should I be looking for in terms of dimensions to make sure I’m finding a stone with a great cut, while still taking advantage of this data driven approach? Thanks!
There’s no official cut grade for cushions. I recommend depth < 70%, table < 63%, and a pavilion facet pattern where the “X” extends all the way to the corners. The pavilion facet pattern is shown on the certificate and is the figure on the right in the pair of figures.
Screening for diamonds with the X all the way to the corners removes the crushed ice cushions. You’ll generally want to avoid the crushed ice cushions for two reasons: 1) they tend to have worse light performance and leak more light and 2) they tend to hide carats in their bulbous pavilion (bottom) so they face up smaller than non-crushed ice cushions.
It might be easier to go to each vendor’s site to apply this criteria. I could highlight the diamonds within the table and depth limits, but I can’t yet automatically screen by facet pattern to highlight the non-crushed ice cushions. You can then visually check the crushed ice vs. non-crushed ice look (it should be visually apparent based on my cushion guide).
If you’d like I can provide some examples that fit your criteria. 1.2-1.5 H-F covers a broad range, so a budget would help narrow the options down.