GCAL (Gem Certification & Assurance Lab Inc.)
Unique suite of certification, identification, valuation, and forensic services for natural and lab grown diamonds, gemstones, and jewelry. Only lab in the world offering a Consumer Guarantee.
gcalusa.com

Gemex
GemEx was created to measure the play of light in a diamond and make it easier for diamond customers to know they are purchasing a beautiful diamond.
gemex.com

GIA
With objectivity and expertise as its hallmarks, GIA ensures the integrity and accuracy of every report it issues. GIA tests every material submitted to determine whether it is natural or not, and discloses any treatments discovered during our examination.
gia.edu

GSI
The GSI laboratory is the genesis of GSI's success. All that GSI is and all that it has accomplished started there.
gemscience.net

Gubelin Gem Lab
One of the world's most renowned and respected gemmological laboratories.
gubelin.com

IGI
World's largest Independent Laboratory for Testing and Grading Gemstones. Inspiring Confidence. Unparalleled Reach. Empowering Trust. Unrivaled Experience.
igi.org

Independent Gemological Laboratories
Independent Gemological Laboratories, was founded on the guiding principles of providing consumers with the information they need to make an informed decision. As we know many jewelers are terrific sales people, but have very little knowledge of the actual gems they are selling.
dia-lab.com