Professional Gem Sciences, Inc. (PGS) with offices in both Chicago and Los Angeles is a full service, gemological laboratory that can identify and certify the quality of your gemstones.
In addition to the PGS certification, the laboratory offers a detailed diamond report (appraisal) known as the Expert Opinion Certificate of Quality. This report describes the Color, Clarity, Cut (shape, proportions and finish), and the Carat weight of a loose diamond. However, perhaps the most important component included in this Certificate of Quality is an accurate mapping diagram or plot of the diamond’s inclusions and surface blemishes. This plotting diagram can then be used to positively re-identify that diamond at any time in the future. This can be achieved even if the diamond has become damaged, and in some cases, even if the stone has been re-cut to try to hinder re-identification.
The PGS Laboratory also offers the verification of diamonds – to make sure that they match with their reports which have been issued by other laboratories. They refer to these reports as a Second Opinion and reduce their charge by up to 50% from our normal fees.
PGS Certified Diamonds wholesale at approximately 8% less than similar clarity & color EGL certified Diamonds.
Advice: Since the PGS is a relatively small grading laboratory and grades a relatively small number of diamonds, we have not inspected enough diamonds with PGS certifications to form an opinion.