2003

GIA Research Conducts Tests on Diamond Appearance

Jan. 2003

GIA scientists want to make their research less applicable to just the lab and more important to the day-to-day life of the industry.

Research scientists are testing how human observers describe and judge diamonds of various proportions under a variety of conditions. Diamond dealers, retailers, consumers and trained observers are taking part in a ongoing serious of observational tests. In the past eighteen months, GIA has collected nearly 40,000 observations of more than 1,000 diamonds in a variety of controlled environments as well as in typical trade settings. Among those who participated were diamond dealers in both New York and Antwerp, who observed the test diamonds in their own office, where they make similar judgments every day.

After the tests, some of the diamond dealers learned the stones’ actual proportions, and were surprised at the performance of a number of diamonds cut to proportions considered outside standard cutting proportions. This supports GIA’s contention that "Every facet matters." GIA has also found that variations in the star and lower-girdle facets greatly impact the stone’s visual appearance. Therefore stones cannot rely on simply pavilion angle, crown angle, table size and table depth.

Research scientists at GIA are currently examining other possible appearance aspects, such as scintillation, to understand how they also might interact with brilliance and fire to determine overall appearance.