Welcome To GIL - Gemological International Laboratories

Gemological International Laboratories (GIL) is an international gemstone testing facility specializing in comprehensive diamond and colored gemstone analysis. GIL provides detailed identification and enhancement reports, country-of-origin reports, as well as complete colored stone analysis documents. The Laboratory is equipped with state-of-the-art instrumentation, and applies standard gemological, as well as advanced analytical, techniques to each determination it makes.

Verify your Certification

An improved turnaround
for laboratory services.

GIL continues to improve the grading process while maintaining faster turnaround times for selected services. While maintaining standards the industry has grown accustomed to GIL ensures the highest grading practices at faster turnaround times.

Instant online report
verification process

An increased effort to maintain additional security measures and to support online commerce, GIL has an online report verification to meet the needs of the industry.

4 C’s
Diamond Guide

Download the GIL 4 C’s Diamond Guide to help you through the buying process.

New Gemstone
Origin Reports

After many years of research at GIL Thailand we are proud to introduce the GIL Gemstone Origin Reports for Rubies, Sapphires, and Emeralds in Red Folders.

Our Expertise

Total commitment to understanding consumer concerns has motivated GIL to develop comprehensive analysis and clear documentation for consumers. This empowers jewelry buyers to focus on finding precisely what they want, with full assurance in the integrity and quality of the GIL certification.

  • Diamond Certificates
  • Colorstone Certificates
  • Jewelry Certificates
  • Colorstone Envelop