Gems & Gemology
Fall 1941, Vol. 3, No. 11
A Solution to Diamond Color Grading Problems
Robert M. Shipley, and 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.