Up to the fourth century, wholesale diamonds were known only in their rough, or crystalline forms. They 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.
When looking at the general appearance of fancy diamond engagement ring, make sure that the stones are appealing to your eye and that their are bilaterally symmetrical.
There are old time diamond merchants and jewelers who believe they can accurately tell ideal cut diamond size and quality with only a loupe, but we have found that they are often wildly off in their estimates.