Montreal School of Gemology - info-lettre-plus

E-Newsletter Plus 2012

The major American labs and their quality reports

The September 2012 issue of Rapaport Magazine features quality reports issued by the major American laboratories. We have selected three of these for the EGM Newsletter and have consulted their websites to summarize their services.


According to Rapaport, young customers and high-end buyers today are increasingly requesting quality reports when they buy diamonds. Young people do research online and want to make sure they get what they paid for, while high-end buyers usually invest more in their purchase and are seeking reassurance.



American Gemological Laboratories (AGL)


Based in New York, AGL test and grade coloured stones exclusively. They provide two types of report: the Prestige Gemstone Report and the GemBrief Report.


The Prestige Gemstone Report is made up of the following three sections.


The image section shows a picture of the stone as well as a diagram with measurements and proportions.


The identification section is divided into three sub-sections: identification, geographical origin when possible (available for rubies, sapphires, emeralds and alexandrites), and treatments divided into Standard Enhancement and Additional Enhancement categories. Treatments can be further detailed into degree of clarity enhancement and stability.


Using AGL’s proprietary grading standards, the grading section reports in detail on the gemstone’s characteristics:




Cut grade



The GemBrief is a credit-card-sized report that provides full identification, a picture, and somewhat simplified enhancement information.


AGL does batch testing and offers a rush service.



American Gem Society Laboratories (AGS)


Based in Las Vegas, AGS is a not-for-profit institution that provides grading services for diamonds only.


AGS cut grade is based on the Laboratories’ patented Angular Spectrum Evaluation Tool (ASET), which analyses the light performance of the stone as it travels through the stone. The cut, which includes polish and symmetry, is graded on a scale from 0 to 10, zero corresponding to “Ideal Cut.”


The ASET is used for round brilliants as well as for princess, emerald, oval and cushion cut diamonds, and for some patented cuts. A diamond graded “AGS Cut Triple Zero” is a diamond whose light performance, symmetry and polish are ideal and each graded zero. An “AGS Triple Zero” diamond is a stone of the highest quality of cut, clarity and colour.


All AGS reports can be accessed online with an iPhone or tablet.


The Diamond Quality Document or DQD


This report gives the four Cs of the stone with a detailed cut grade according to AGS proprietary cut grading system, along with the stone profile view including measurements and proportions. The report also shows a clarity diagram and grading scales for cut, colour and clarity.


The Platinum DQD* includes all the information contained in a DQD, plus a computer-generated light performance map.


The Diamond Quality Report or DQR


The DQR contains the same type of information as the DQD. However, the cut is analyzed according to Proportions (total depth percentage, table percentage, type of girdle and culet) and Finish (Polish and Symmetry) and not from 0 to 10.


The Gold Diamond Quality Report or Gold DQR *

This report is used for round diamonds only. It contains the same information as the DQR.


The Diamond Quality Analysis or DQA

The DQA is a pocket-sized report for stones weighing up to 1.99 ct. It includes the 4 Cs, but no plotting. All DQA stones are laser inscribed with a report number.


The Diamond Consultation or DC

The DC in a credit-card-sized format provides the 4Cs and plotting of the inclusions for diamonds up to 4.99 cts. Enables rapid identification for a very reasonable fee.


*Can be used for both natural and lab-grown diamonds




Gemological Institute of America (GIA)


The GIA is the oldest and most well-known American lab. This not-for-profit organization grades natural and synthetic diamonds, coloured stones and pearls.


Based on proportion and finish, the GIA grading system is the standard for many certified round brilliant diamonds in the world. The cut is graded from Excellent to Poor.


The GIA website is very user friendly and it’s easy to find all the information you need about GIA certification services.





The Diamond Grading Report is available for loose natural diamonds over 0.15ct. It includes the 4 Cs, a plotting of inclusions, and a diagram of the stone’s dimensions and proportions in profile. Limitations: the GIA Diamond Grading Report is not available for synthetic diamonds, set or treated diamonds with unstable treatments such as fracture filling and coating. Treatments such as lasering of inclusions or HPHT are clearly mentioned in the report.


The Diamond eReport includes the same information as the Diamond Grading Report, plus a detailed face-up image of the stone. Available for natural diamonds up to 2.99 cts. Available online only through Report Check.


The Diamond Dossier is smaller in size than the Diamond Grading Report but includes the same information except plotting of inclusions. The report number is laser engraved on the girdle. Available for loose natural diamonds over 0.15ct.


The Colored Diamond Grading Report for naturally coloured or colour enhanced loose natural fancy coloured diamonds over 0.15ct. Includes the 4C’s; a picture of the stone is optional.





The Synthetic Diamond Grading Report provides the 4Cs with less detail than for natural diamonds. The girdle is engraved with its report number and a statement that the stone is laboratory grown. The same limitations as for the Diamond Grading Report apply.


The Synthetic Colored Diamond Grading Report’s content is the same as for its natural counterpart.





The Colored Stone Identification Report documents the full gemmological examination of a material. Shape, cut, dimensions, weight, transparency and colour are detailed on the report, which also includes a colour photo. It states whether the material is natural or synthetic, treated or untreated. Natural rubies, sapphires, emeralds, tourmalines and alexandrites reports are tailored for these popular gems.


The Colored Stone Origin Report is available for rubies, sapphires, emerald and tourmalines. The report includes all the Colored Stone Identification Report information plus the geographical origin when it can be determined.


The Colored Stone Analysis Report. Besides the identity of the stone, this report provides the full data from which conclusions were reached. 


For coloured stones, the GIA will issue reports on rough or polished material, loose or mounted.





The Pearl Identification Report details the quantity, weight, size, shape, colour, origin (natural or cultured in saltwater or freshwater), mollusc if determinable, and any detectable treatments for loose, mounted or strung pearls.