One, Two, or Three carats, which shall you choose? This photo compares all three carat weights in diamond solitaire engagement rings. All of these appear to be round brilliant cut stones with four prongs. That takes care of carat and cut but certainly don't forget the clarity and color of the diamond also. You really must check clarity and color in person. Best wishes, I hope you receive the one of your dreams.....the man, that is ;) .... then the ring !!!