Ans: i. It won't be attracted by a magnet. ii. A clean piece of copper has a pinkish tone that looks red, yellow, or orange after some time. iii. The sound of genuine copper is profound and smooth instead of sharp and tinny. iv. Copper is not controlled by the Unified Numbering System. It is not copper if there is "C" marked on it and trailed by numbers as this occurs on metals.