Boston Gem Laboratory
Expert Appraisers of Modern, Contemporary and Vintage Jewelry
Jewelry always remains in the clients possession
Diamond Clarity Grading Scale of the Gemological Institute of America
Diamond Color Grading Scale of the Gemological Institute of America
The Gemological Institute of America (GIA) Laboratory grades the cut of round diamonds based on computer modeling and observation.
The American Gem Society (AGS) Laboratories grades the cut of round diamonds and fancy shapes based on actual light performance; brightness, dispersion, leakage and contrast.
Boston Gem Laboratory (BGL) grades the proportions of round diamonds and fancy shapes based on light performance using GIA and AGS parameters.
COLORED STONE CUT GRADING:
Boston Gem Laboratory (BGL) grades the cut of colored stones based on GIA grading for brilliance, windowing, extinction, symmetry, crown height and pavilion depth, bulge and girdle thickness, table size and finish.
Note: Diamond cut and light return are not always equal. A diamond that is average in cut may exhibit above average light return performance, however, a well-cut diamond maybe average in light return performance.
Knowing the quality of your jewelry before you buy or sell is absolutely necessary.
"Protecting and preventing consumer
fraud
through knowledge"
BOSTON GEM LABORATORY ~ rev.06Aug14