I recently went to Zales to purchase an engagement ring. The ring I am interested in buying was listed for $10,999. With discounts and after negotiating, they will sell it to me for $8500. Its a 2 carat round solitaire. Color H Clarity I1. Its certified by GSI. I have been doing some research and have found that GIA and AGS seem to be the most trusted. The diamond looks pretty clear (white, not yellow) and the flaws aren't clearly visible (you can see some if you look very closely though). I went to Helzberg and Kay and they both said that a 2 carat diamond with that color and clarity sold for $8,500 is hard to believe. They advised that I go back and see who has certified it. From the looks of the diamond, I do plan to buy it. I looked at 1.5 carat diamonds at Helzberg and Kay (GIA Certified) which they offered to me at the $8k - $9k range and went back to Zales and looked over the 2 carat more closely. I am still leaning towards the 2 carat from Zales, but am a little worried about the GSI and what that means exactly. What do you think? What do I have to worry about if I buy the 2 carat that is GSI Certified, as opposed to the 1.5 carat thats GIA Certified?