| Site | Category |
| The Jewellery Valuation Centre | Appraisers |
| The Jewelry Appraiser Inc. | Appraisers |
| The National Association of Jewelry Appraisers | Appraisers |
| The National Association of Jewelry Appraisers | Appraisers |
| Teletrade Auctions | Auctions |
| The Diamond Broker | Diamond Dealers - Wholesalers |
| The Diamond Connection | Diamond Dealers - Wholesalers |
| The Diamond District | Diamond Dealers - Wholesalers |
| TheFinestJewelry.com | Diamond Dealers - Wholesalers |
| TheJewelryDoc.com | Diamond Dealers - Wholesalers |
| Timanttiala Oy - Gem Diamonds Ltd. | Diamond Dealers - Wholesalers |
| TMW Diamonds Inc. | Diamond Dealers - Wholesalers |
| touslesdiamants.com | Diamond Dealers - Wholesalers |
| Tradeshop Inc. | Diamond Dealers - Wholesalers |
| Treasures by R.J. | Diamond Dealers - Wholesalers |
| Triad Diamonds Corp | Diamond Dealers - Wholesalers |
| Trillion Diamond Co. | Diamond Dealers - Wholesalers |
| twin-diamonds | Diamond Dealers - Wholesalers |
| Twinkle Diamonds | Diamond Dealers - Wholesalers |
| Twinkle Imp-ex P/l | Diamond Dealers - Wholesalers |
| The Electronic Guide - UK | Diamond Districts |
| The Source -Israel | Diamond Districts |
| The Ultimate Diamond Information Site | Diamond Districts |
| TMW Diamonds | Diamond Manufacturers |
| TMW Diamonds Inc. | Diamond Manufacturers |
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