Accredited Gem Laboratory

The following requirements must be met for a firm to qualify as an Accredited Gem Lab (AGL). These requirements will be reviewed and updated based on current needs and technological developments. 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 member firm and have physical space dedicated to the proper use of the gem testing equipment;
3. The firm must have the laboratory equipped with the following testing instruments, tools, and reference material, as a minimum:
   
   1. An adequate and current gemological library which may be physical, digital, or online
   2. Color master diamond comparator set, consisting of at least five (5) master diamonds that have been graded by GIA or AGS Laboratories, and meet the requirements as a qualified master set. For more information and qualifications, please reference the Color Master Requirements section on this page.
   3. Color comparison set for colored gemstones and fancy colored diamonds such as Gem Dialogue^®, Munsell Color^®, GIA^®, GemeWizard^®, ColorCodex™, or similar
   4. Darkfield binocular microscope (minimum 10x with overhead fluorescent light attachment)
   5. Carat scale capable of weighing accurately to 0.002 carats (1/5 point) with calibration capabilities
   6. Dichroscope
   7. Internet connection
   8. Lighting source: Daylight equivalent (approximately 6500 degrees Kelvin) or standardized color grading environment (GIA DiamondDock® or similar)
   9. Measuring device (Leveridge gauge or millimeter gauge)
   10. Metals tester
   11. Photography equipment (cell phone or digital camera acceptable)
   12. Polariscope
   13. Refractometer with polarizing plate and RI fluid
   14. Laboratory-grown diamond screening and detection equipment (recommended standards are listed in the Diamond Screening Equipment Recommendations section of this page)
   15. Ultra-violet light, both longwave and shortwave

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

1. 1. Diamond tester (thermal and electrical conductivity meters to screen for diamond simulants)
   2. Fiber Optic Light Source
   3. Non-Contact Optical Scanner
   4. Spectroscope
   5. Gemstone Identification Filters
   6. The most current edition of The Practical Guide to Jewelry Appraising by Cos Altobelli, ECGA; and
   7. Carat scale attachments/hydrostat for determining specific gravity

An Accredited Gem Lab^® must be operated in a professional and ethical manner, in accordance with the Membership Standards of the American Gem Society. Any member who operates a laboratory in such manner as to bring discredit upon the Society, by unwarranted discrediting of a competitor’s merchandise, or by any other unethical conduct, shall be subject to probation, suspension, or expulsion from the Society or any other action recommended by the Grievance & Review Subcommittee.

An Accredited Gem Lab^® is subject to audit without notice for compliance for the above elements. If the audit identifies non-compliant elements, the titleholder that oversees the AGL (AGL Principal) will have one (1) year from the date of Notice of Non-Compliance to rectify any issues that would cause non-compliance.

Download Requirements

To qualify as an Accredited Gem Lab^® (AGL), a set of at least five (5) diamond color masters is required. Color master diamonds must be graded by GIA or AGS Laboratories as master color grade diamonds, and must satisfy the following requirements.

REQUIREMENTS

Color: The first diamond must be AGS 0.0 (D), AGS 0.5 (E), or AGS 1.0 (F). Each additional diamond can have no greater variation than one (1) numerical AGS color grade or the second GIA letter grade 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 “AGS Colorimeter Values” if the diamonds were previously graded at AGS Laboratories.

Color Scale:

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. Due to differences in depth, there can be variations in the appearance of color in a shallow diamond compared to a deeper diamond. This can make accurate comparisons more difficult. All diamonds in the set should be 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 0.25 carats or more and must be unmounted. It is recommended that the diamonds in the master set are within 0.10 carats of each other. 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 must be laser inscribed as an identifier to ensure there are no possibilities of mistaking a master diamond for a diamond being assessed. The inscription must be the GIA color master inscription or the AGS number, estimated Colorimeter value, and the equivalent master color grade.

Download Requirements

The following table outlines the recommended standards for laboratory-grown diamond screening and detection equipment needed to qualify as an AGS Accredited Gem Lab^®.

The above recommendations are based on key metrics used for the testing of diamond verification instruments by Project ASSURE. The results of all instruments tested are available in the ASSURE Directory. When choosing a diamond verification instrument to purchase, please visit the ASSURE Directory to help make a decision based on the accuracy metrics listed for each instrument. Project ASSURE provides a third party assessment of all instruments submitted.

For the most up-to-date information, please visit the ASSURE website at naturaldiamonds.com/council/assure-diamond-verification. Testing is ongoing on new equipment and the instruments list on the ASSURE Directory may be updated from time to time.

Download Requirements & Equipment Recommendations

Do you meet the requirements to become an Accredited Gem Lab^® (AGL)? If so, apply today by completing this application and submitting to [email protected].

Questions? Contact membership at [email protected] or 866.805.6500, option 3. 

Download Application