I am in the market for a special diamond. Originally, I was searching for a 4-5 carat Emerald, D color, FL clarity, with excellent polish and symmetry, and no fluorescence, that was a type 2a diamond. However, I came across a diamond that meets all these specifications but is a type 2b. After doing some research, it appears that type 2b diamonds are very rare (according to quick google search type IIb diamonds make up about 0.1% of all natural diamonds). I am curious if there is any reason I should buyer a type 2a vs type 2b diamond.