During the Ming Dynasty, in order to conserve the supply of this beautiful stone, the Empire allowed it to be mined only with government permission.
田坑採石需要很高的經驗與技巧，工人先用鐵棍插入田中四處探測，若遇硬物，即予掘起。挖出的石頭通常外表粗糙，貌不驚人，須經鐵鋸、鑽刀層層切割，方知是否有所獲。若能獲得一小方美石，自是萬分幸運。