One of the two principal engagement rings trade routes passed through Venice. It enjoyed a monopoly of the ideal cut trade on its way to the main towns of southern Germany up to its final destination in Bruges.
The first step in manufacturing diamond engagement ring is to give them to a cleaver or sawyer. They both, essentially, perform the same task: That is to cut--or cleave--the ideal cut in two pieces in order to bring out the best profile that will determine the end product of the stones.
How the jewelry has been cut, polished and to what proportions and symmetry are important, as these factors determine the life, brilliance and dispersion of the ideal cut. If the cutting factors fall below standard the appearance of the ideal cut is adversely affected.