Bill Bray
Bill Bray
Last 5 articles of this author
Upper Halves – Counter Point
Fri, 25 Mar 2005
The opening paragraph of the article presents a concept that indexing top halves produces different amount of weight retention. This is correct, although not as dramatic as presented. A diamond cutter knows that brilliandeering an entire diamond calls for a weight loss of approximately 4%. This causes one to question the facts presented in the conclusion of this article Setting a Constant Girdle Thickness at the Mains which shows a range of finished weights from .866 cts. (Index 3) to .774 cts. (Index 1) or 11%. As noted, these findings are outside the parameters of realistic cutting. The results presented in the article were accurate when they concluded that a fraction of a point was lost by cutting the top halves in different configurations (stating that the Index 1 stone was .817cts. VS the Index 3 stone of .808cts.), but the results change upon further examination of indexing with relation to diameter, and then change more so in setting constant girdle thickness at the mains, which in a normally cut stone is not a product indexing the upper girdle halves. Girdle thickness can only be increased by adding more girdle (read reducing the diameter of the stone) either by bruting or faceting or polishing.
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Upper Halves – Counter Point
Fri, 25 Mar 2005The opening paragraph of the article presents a concept that indexing top halves produces different amount of weight retention. This is correct, although not as dramatic as presented. A diamond cutter knows that brilliandeering an entire diamond calls for a weight loss of approximately 4%. This causes one to question the facts presented in the conclusion of this article Setting a Constant Girdle Thickness at the Mains which shows a range of finished weights from .866 cts. (Index 3) to .774 cts. (Index 1) or 11%. As noted, these findings are outside the parameters of realistic cutting. The results presented in the article were accurate when they concluded that a fraction of a point was lost by cutting the top halves in different configurations (stating that the Index 1 stone was .817cts. VS the Index 3 stone of .808cts.), but the results change upon further examination of indexing with relation to diameter, and then change more so in setting constant girdle thickness at the mains, which in a normally cut stone is not a product indexing the upper girdle halves. Girdle thickness can only be increased by adding more girdle (read reducing the diameter of the stone) either by bruting or faceting or polishing.
