| Business | Phone |
| Barco Gem Co 10 Rockefeller Plz # 810, New York 10020 | (212) 307-1777 |
| Global Gem Corp 425 Madison Ave, New York 10017 | (212) 350-9936 |
| Independent Gemological Lab 21 W 38th St, New York 10018 | (212) 557-0111 |
| International Colored Gemstone 19 W 21st St # 705, New York 10010 | (212) 352-8814 |
| James Garriti Lapidary 70 Bowery # 202, New York 10013 | (212) 226-7911 |
| Universal Gemological Lab Inc 71 W 47th St # 204, New York 10036 | (212) 921-3324 |
| Royal Precious Gems Inc 15 W 47th St, New York 10036 | (646) 728-0151 |
| Star Diamond Trading Co Inc 1285 Avenue Of The Americas, New York 10019 | (212) 974-1000 |
| Mdk Gem House Inc 48 W 48th St, New York 10036 | (212) 221-1236 |