Talk:Penny's Team/@comment-67.82.144.215-20151208211655/@comment-86.153.151.78-20160209192305

@ ChunsioKunin Copper is a transition metal, which have the unique property of having brightly coloured compounds and multiple valencies. For example, Iron (II) Oxide is green, but Iron (III) oxide is red.

Copper compounds can and do come out in sapphire blue shades, such as copper sulphate, a soluble crystal that has a reversible reaction (turning into white anhydrous copper sulphate when heated and turning blue again when water is added).

Finally, bronze and brass are both copper compounds, one is brown and the other is gold.