Gems & Gemology
Fall 1941, Vol. 3, No. 11
A Solution to Diamond Color Grading Problems
Robert M. Shipley, と R.T. Liddicoat
Although GIA’s system for evaluating diamond quality has been an industry benchmark since 1955, it all began with the efforts of Robert Shipley Sr. and Richard T. Liddicoat a decade earlier. This 1941 article troubleshoots the challenges of evaluating diamond color, including the need for controlled light in a standardized, consistent environment. The authors describe a prototype instrument called the Diamolite, which filters and diffuses light for consistent results, and introduce the GIA Colorimeter, a scale for measuring stone color.