Provides technical and gemological appraisal and consulting services to the trade and the public. Services, articles, and links.

Provides diamond grading services featuring grading of the diamond cut.

Provides diamond, colored stone and pearls certification, analysis and consultations for the jewelry trade. Produces educational and promotional materials.

Specializes in origin of color determination for fancy colored diamonds using Raman spectrometer. Offers diamond grading reports and appraisal services.

Offers gem grading and identification services and gemmological courses for the trade and members.

Determination of the authenticity and country of origin of a rubies and sapphires. Offers gemstone reports and inscriptions.

Provides grading and identification of diamonds, colored stones or pearls for the industry and consumers.

Offers mini and full diamond grading reports and appraisals for the trade. Located in Bellevue, Washington

Independent service provides general information on gemstones, ongoing research and lab report services.

Fine jewelry appraisals by an independent team. Services, price list, and location map. In Manchester, CT.

Technical advisers, appraisers, gemological training. Services, background, and contact information. Located in Brazil.

Offers gemstone analysis software, gemological education, and gemological laboratory services. Includes articles on diamond cut studies and a gallery of virtual diamond images.

An independent, international, non-profit organisation dedicated to the identification, treatment, and origin. Services, education, and contact information. Located in Switzerland.