| Business | Phone |
| Diamond Dealers Club 580 5th Ave # 10, New York 10036 | (212) 790-3600 |
| G & W Tool Co 10 W 47th St # 1209, New York 10036 | (212) 391-2570 |
| S & I Diamonds Drilling Inc 15 W 47th St # 207, New York 10036 | (212) 869-7557 |
| S M Grotell Design Inc 11 W 25th St # 9, New York 10010 | (212) 741-7952 |
| Samuel Lam Inc 37 W 47th St # 203, New York 10036 | (212) 719-2276 |