Q&A: Help Picking a 1.25 Ct. Round Diamond for a White Gold or Platinum Solitaire Setting

Hi, I was recommended to you by my friend who recently got engaged with your help. I am looking to propose approximately 3 weeks from now, so am working on an expedited time scale. I have done some research and have a rough sense of what I want to purchase: round cut, around $10k, approximately 1.25 carats (1.2 to 1.3 seems to be the realistic range for the quality I want). In terms of cut, clarity and color, I think my priorities are in that order based on my research, but please let me know if you advise otherwise.

Below are 3 diamonds I have come across on James Allen. What are your thoughts on these? Do you prefer any one, and do you also think that these are each a “good deal” for the price? Given my general requirements, I would most appreciate your advice on deciding among diamonds of roughly the same price/size/quality and confirming that the price is a reasonable one.

1. https://www.jamesallen.com/loose-diamonds/round-cut/1.25-carat-h-color-vvs2-clarity-excellent-cut-sku-325899?a_aid=dmnd1357

2. https://www.jamesallen.com/loose-diamonds/round-cut/1.29-carat-g-color-vs1-clarity-ideal-cut-sku-421249?a_aid=dmnd1357

3. https://www.jamesallen.com/loose-diamonds/round-cut/1.23-carat-h-color-vvs2-clarity-excellent-cut-sku-457575?a_aid=dmnd1357

More generally, can you bargain with James Allen in the same way you can bargain in store? I understand that James Allen takes about 2 weeks to ship, so am looking to finalize at the end of this week, but please let me know if you think I should keep looking.

Thanks! 

Thanks! Setting wise, something simple and traditional: I think the six prong simple band without any other stones. I think platinum or white gold: which do you recommend? 

Thanks. What are the key differences between white gold and platinum?

In terms of the diamond, I think quality is more important to me than size but thanks for the suggestion. If you think the ones I pointed out are “good deals” I will probably go with one of them unless you recommend another one similar to them. Thanks.