Buyers might choose a 1.20 carat diamond if they have purchased a 1 carat diamond in the past. They might choose to upgrade their diamond to increase size. Perhaps the 1.20 carat weight has a significance by number, or maybe the cost fits a specific budget for diamond colour and clarity. There are many reasons why a buyer will choose to exceed the 1 carat size. But unlike a small step to 1.10 carats, the 1.20 carat size gives a greater difference in physical size by comparison to the 1 carat diamond. [links]