I’m quite overwhelmed with all the different parameters in terms of round diamonds and how much they really matter. Does the Halloway Cut Advisor really matter? Is falling within both AGS and GIA in your cut estimator crucial? Can you help me pick out some round diamonds in the 1.2-1.3 carat range that will look nice in a platinum setting and are worth the price?
No, I don’t think the HCA matters. It’s a black box algorithm that reflects one man’s opinion on how a diamond should look, last updated in 2003 before the release of the AGS and GIA cut grade systems in 2005. It fails as a numerical measure (the difference between 2.6 and 2 is not the same as 2 and 1.4), giving a false sense of numerical precision. Good old gold has an in-depth write-up of its limitations. And it’s not pushed anywhere except on pricescope. I prefer to rely on the GIA and AGS cut grade systems, which are published and vetted.
Qualifying as both GIA Ex and AGS 0 Ideal will ensure good light performance. You can generally find such a diamond for the same price as a less well-cut stone, so there’s not much reason to consider diamonds with non-optimal proportions.
Your budget easily accommodates 1.2-1.4ct diamonds. I think H is the best value for a platinum ring – you shouldn’t notice the color. The options below all have optimal proportions. The VVS1 and VVS2 diamonds are on the cost-efficiency frontier for their specs and would be good deals down to SI1/VS2, so you’re essentially getting the clarity for free.
Diamond List – Generated by https://www.diamondscreener.com/diamond-prices/