GemNotes

GIA Study Method Is Flawed, Expert Says The Gemological Institute of America’s recently published study on diamond proportion and brilliance prompted many to question its conclusions, contending that its critique of current diamond-grading systems is premature without a consideration of fire or scintillation. Now, an accomplished researcher has criticized the very scientific model on which the GIA study authors based their conclusions. In a letter to the editor in the Winter 1998 issue of GIA’s Gems & Gemology journal, Martin Haske says GIA’s use of three-dimensional hemispherical lighting represents a “fatal flaw” in the study. Haske, who designs and produces high-tech gemological equipment for jewelers and gem laboratories, recognized that the hemisphere, which covered the diamond and stopped at the girdle plane, favored shallow crown angles and possibly larger tables
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