And white copper is one kind of copper-zinc alloys.It is also called Chinese silver in ancient times abroad.The fineness of Tibetan silver is not high.There are some inpurities in it.The black colour is especially made in common ornaments and its main ingredients is plant ash. And white copper is one kind of copper-zinc alloys.It is also called Chinese silver in ancient times abroad.The fineness of Tibetan silver is not high.There are some inpurities in it.The black colour is especially made in common ornaments and its main ingredients is plant ash.