PGGL offers a variety of diamond grading certificates for consumers and trade. Using ImaGem’s direct measurement technology in conjunction with expert trained gemologists, PGGL offers trade members and consumers, a new level of accuracy and precision in diamond grading. All diamond grading certificates are backed by PGGL’s diamond grading guarantee.

The basic certificate includes information on the 4Cs (color, clarity, carat weight and cut), fluorescence, proportion measurements, symmetry, alignment and craftsmanship grade. Add on services are available for light behavior analysis and clarity plots. All grading is based on measurements taken using ImaGem’s equipment.
Special customization services are available to trade members for volume orders. Further details are available upon request.

  • Direct measurement technology: data on the Certificate is measured from the actual diamond – and not estimated from a model
  • Patented ImaGem technology offers face up view of table and side view of profile showing how well a diamond has been crafted
  • We guarantee the results on our Certificates!
  • Unprecedented accuracy and repeatability
  • Costs less than 1/3rd of Certificates from other labs
  • Guaranteed 48 hour turnaround
PGGL Grading Certificate with Clarity Plotting and Light Behavior
PGGL Grading Cert with Light Behavior
PGGL Grading Certificate with Clarity Plotting

PGGL Grading Certificate


Performance Specifications

  • Gauging: ± 0.005mm with 2 Sigma probability for linear measurements for all sizes except for table. Repeatability for angles depends on size of stone.
  • Color: ±1/3rd of a Color grade with 2 Sigma probability.
  • Clarity: ±1/2 of a Clarity grade
  • Fluorescence:  ± 0.03 with 2 Sigma probability on C.I.E. (Commission Internationale L’ Eclairage, France) XYZ scale.
  • Light Behavior: ±2% of Brilliance; ±2% of Sparkle; ±4% of Intensity – all with 2 sigma probability.