Cutting the Upper and Lower Halves (5.40)
The upper and lower halves are dug out of the girdle of the diamond in the cutting process. Before the cutter starts the “brillianteering” (upper/lower halves and stars), the girdle of the diamond will have been left thick enough, to allow room to form the upper/lower halves. Each of these facets should be dug out enough to create an obvious angle difference between it and the main facet (kite shape) right next to it. The further a girdle facet is dug, the greater is the angle it creates. There are extremes to this also. A “pasted” facet has very little angle differentiation; sometimes this can be so slight that you have to look twice to recognize its presence. This causes a large reduction in brilliance depending on the degree of severity. At the other extreme, a cutter will often over-dig the halves to thin down a girdle that is “Extremely Thick”. This is easily spotted by the large difference in girdle thickness between the upper and lower halves and between the crown and pavilion mains. This may also be referred to as a “scalloped girdle”.
