| Site | Category |
| Rose Galleries | Auctions |
| ROYAL ASSCHER DIAMOND COMPANY | Diamond Cutters |
| R&S Gold Finland Ltd | Diamond Dealers - Wholesalers |
| RDI Trading | Diamond Dealers - Wholesalers |
| Robert Moskovitz Co. | Diamond Dealers - Wholesalers |
| ROCHESTER DIAMONDS INCORPORATED | Diamond Dealers - Wholesalers |
| Romance Diamond Company | Diamond Dealers - Wholesalers |
| Rony Paz Trading, LLC | Diamond Dealers - Wholesalers |
| Rosy Blue Jewelry | Diamond Dealers - Wholesalers |
| Royal Diamonds World | Diamond Dealers - Wholesalers |
| RS Imports | Diamond Dealers - Wholesalers |
| RS Imports | Diamond Dealers - Wholesalers |
| Russian Diamonds Syndicate | Diamond Dealers - Wholesalers |
| RDI DIAMONDS INC. | Diamond Manufacturers |
| RDI Trading | Diamond Manufacturers |
| RONY PAZ TRADING | Diamond Manufacturers |
| Rosyblue | Diamond Manufacturers |
| Royal Diamond Cutter | Diamond Manufacturers |
| Rubin & Zonen | Diamond Manufacturers |
| Rubin & Zonen | Diamond Manufacturers |
| Rex Diamond Mining Corporation | Diamond Mining |
| Rimfire Pacific Mining NL | Diamond Mining |
| River Diamonds Limited | Diamond Mining |
| Radio National's Diamond Resources | Education |
| Roberto Filippi | Gemological Labs |
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