1. color (bai appearance), visual observation
2, solid du quality (most of the iron alloy zhi) can be used with a Tao magnetic version of the article, such as magnets, with magnetic tools, etc., the right to discriminate.
3. weight, i.e. density.
4, manufacturers, general purchase of copper supplies to go to the formal manufacturers, formal channels to buy. And carefully check

Copper mainly depends on his color, purple copper, red copper is good copper. There are brass, color hair light. There are also copper plated with a zinc, some tin, white, there is a low-quality copper, copper inside impurities, with a bend in the hand broken into two, which has black impurities.