by Babyboychoy » Aug 16, 2015 Costco is my hubby's favorite store. In order to make him feel his money well spent, I agreed to buy diamond from there. We are looking at 2ct and above. I really don't mind buying my diamond from there, they have GIA cert etc and very good return policy. The problem is do you know they have inscription number in diamond? If I take it to local or online store for a Tiffany style reset, how do I know that's my original diamond? Does costco have good price and their stone is top quality? Thanks a lot!