| COMPANY NAME | CONTACT PERSON | CONTACT NUMBER |
| BIG LAB RESEARCH | Ben Hoo | 82024102 |
| GEMOLOGICAL IDENTIFICATION RESEARCH LABORATORY | Mohamed Sabir | 91067267 |
| NAN YANG GEMOLOGICAL INSTITUTE | Zeng | 90683118 |
| UNIVERSAL GEMOLOGICAL LABORATORY | Farhan | 91774997 |
| SINGAPORE GEMOLOGY AUTHORITY | Walter Tan | 97979101 |
| GEMRIGHT GEMOLOGY PTE LTD | Wei Hong | 92487558 |
