System and method for providing a gem assessment based upon proportional parameter values relating to the proportions of a gem, such as a diamond. A gem cut quality rating is provided. The system and method are particularly suited for use in an online environment or may be utilized in conjunction with rough diamond analysis instruments in order to provide cutters with greater guidance as to the most appropriate dimensions to cut rough diamonds in order to maximize the yield of a rough diamond and to also produce a diamond of an acceptable grade.