Accredited Gem Laboratory

The American Gem Society (AGS) Gemological Sciences Committee is dedicated to keeping the Accredited Gem Lab^® (AGL) designation relevant, which helps support the AGS mission of consumer protection, ongoing education, and a high standard of business ethics. As a result, the requirements to qualify as an AGS Accredited Gem Lab^® are currently being reviewed and updated. Please note that these requirements must be met by a Retail or ICGA firm member holding, or applying for the AGL designation:

1. The firm must have a Certified Gemologist (CG)^® or Certified Gemologist^® Appraiser (CGA or ICGA) in its employ to directly supervise the gem laboratory;
2. The firm must have the laboratory located within the premises of the firm member and have physical facilities permitting the proper use and display of the gem testing equipment;
3. The firm must have and maintain an adequate and current gemological library which may be virtual or online and must include an edition of The Practical Guide to Jewelry Appraising by Cos Altobelli, ECGA; and
4. The firm must have the laboratory equipped with the following testing instruments, tools and reference material, as a minimum:
   
   1. AGS Color Master Diamond Comparator Set, consisting of at least five AGS Master Diamonds which have been graded by the AGS Laboratories for color according to the AGS color scale. The girdles must be polished or faceted and laser inscribed to identify them as Master Diamonds. (See Color Master Requirements below)
   2. Color comparison set for colored gemstones and fancy colored diamonds such as Gem Dialogue, Munsell, GIA, GemeWizard, AGL ColorCodex or similar
   3. Darkfield binocular microscope (minimum 10x with overhead fluorescent light attachment)
   4. Diamond scales to 1/100 carat, scale attachments/hydrostat for determining specific gravity recommended
   5. Dichroscope
   6. Internet connection
   7. Lighting source: Daylight equivalent (approximately 6500 degrees Kelvin)
   8. Measuring device (Leveridge gauge or millimeter gauge)
   9. Metals tester
   10. Photography equipment (cell phone or digital camera acceptable)
   11. Polariscope
   12. Refractometer with polarizing plate and RI fluid
   13. Laboratory-grown diamond screening and detection equipment with minimum standards (See Approved Diamond Screening Equipment below)
   14. Ultra-violet light, both longwave and shortwave
       
       

It is also recommended, but not required that the firm have:

1. 1. Diamond probe (thermal and electrical conductivity meters to screen for diamond simulants)
      
   2. Fiber Optic Light Source
   3. Non-Contact Optical Scanner
   4. Spectroscope
      
      

An Accredited Gem Lab^® is subject to audit without notice for compliance for the above elements. If the audit identifies noncompliant elements, the titleholder that oversees the AGL (AGL Contact) will have two years from the date of notice of noncompliance to bring the AGL back to good standing.

Download Requirements

The following outlines the requirements for the AGS Color Master Diamond Comparator Set for the Accredited Gem Lab^® (AGL) designation. 

If you have a set but it has not been graded by AGS Laboratories, please click here to complete a client application and our client services team will work with you to get your set graded.

The following explains our pricing and policy.

PRICING

• First Stone $78; Rejected Stones $19
• Additional Stones $52; Replacement Stone after Reject $78
• Laser Inscription $15

REQUIREMENTS

Color: The first diamond must be 0.0 (D), 0.5 (E) or 1.0 (F). Each additional diamond can be no greater than one (1) numerical AGS color grade variation from the previous diamond. For example, if the first color master diamond is an AGS 0.5 (E), the next diamond must be an AGS 1.0 (F) or AGS 1.5 (G). Single or split grades may be assigned according to the Colorimeter Conversion Table under “Grading Results”.

Fluorescence: Master diamonds must not have visible fluorescence. Since fluorescent diamonds can vary in color grades between daylight and artificial light, they are not appropriate color masters. In colors lower than AGS 3.5 (K), faint fluorescence may be accepted. 

Cut: Diamonds should conform to the same general proportions. The difference in the appearance of the color of a shallow diamond and a deep diamond, due to the additional depth of the latter, make accurate comparisons more difficult. All diamonds in the set should be of approximately the same size and proportions. 

Clarity: Slightly included diamonds are acceptable, providing that the characteristics do not affect the color or transparency of the diamond. 

Weight: Diamonds must weigh 0.30 carats or more and must be unmounted. This size is adequate for comparison of diamonds up to 1.00 carat. 

Girdle: Diamonds must have polished or faceted girdles and there should not be large girdle thickness variations from one stone to another. 

Laser Inscription: Each Color Master Diamond will be laser inscribed with the AGS number, estimated Colorimeter value, and the equivalent master color grade.

GRADING RESULTS 

The diamonds will be returned in individual stone papers. Each paper will note the weight, master number, stone number, measurements and the color grade information. The AGS estimated Colorimeter value will be noted, as will the equivalent letter grade. The Colorimeter value indicates the upper or lower limit of the AGS color grade of the diamond (see conversion table below).

Download Color Master Requirements

The following equipment from the ASSURE Directory of Diamond Verification Instruments will qualify for the Accredited Gem Lab^® designation: 

Download Requirements & Equipment List

Do you meet the requirements to become an Accredited Gem Lab^® (AGL)? If so, apply today by completing this application and submitting to membership@ags.org.

Questions? Contact membership at membership@ags.org or 866.805.6500, option 3. 

Download Application