The first step in manufacturing butterfly ring is to give them to a cleaver or sawyer. They both, essentially, perform the same task: That is to cut--or cleave--the diamond fashion in two pieces in order to bring out the best profile that will determine the end product of the stones.
Extremely subtle color differences can be very important to determine rarity of loose diamonds, but are never a critical factor in beauty.
Up to the fourth century, butterfly ring was known only in it rough, or crystalline forms. It came in a variety of shapes, the most common being the octahedron. This was a crystal with eight faces, resembling two pyramids joined at their bases.