Gems and Jewelry industry is one of the growing industries in Thailand. Not less than 17.7% of the exporting value from this industry is from diamond. Approximately 70% of total exporting diamonds are polished diamond. With the reputation of “Bangkok Cut”, the exporting rate seems to grow rapidly. However while we enjoy the export growth of these gems, the value add to diamond jewelry is still low. An attempt is made in this study to investigate the whole supply chain from rough cut diamond to polished diamond and to diamond jewelry. The diamond supply chain is modeled by SCOR model. Problems in the chain are reflected. It is found that Thailand has a potential to become the diamond exchange centre of the region. Surprisingly, the idea of value chain for gems to jewelry cannot be achieved. Instead, we test the solution of Virtual supply chain via E-marketplace. The architecture of this virtual exchange network is proposed. The strategy enforcing this network is then positioned.