Precious stones are produced in Brazil and Argentina. They are also found in Cambodia and Myanmar. They are also found in Africa. But different countries of gem processing technology and skills is not the same! Some of them are rough, the craftsman processing and then sold in souvenir shops. some, that can be treasured, expensive , can be heirloom of the treasure. I think craftspeople all over the world should have an unified evaluation system giving licenses for different trades. When their products are sold in the global market, there is a standard, which can give a good value! And these craftsmen can be measured and used while they are on the move.