English: Copper is an abundant and quite inert metal with a golden-red color, which is useful for a lot of different things. It is known since ancient times and was the first metal used by humans. Together with tin, it is main ingredient of bronze. In an alloy together with zinc, it forms brass. Copper has a very high electrical conductivity, so it is used for most electrical lines (copper wire). Sometimes copper nuggets like this can be found, but most copper is won from ore. Copper also is a necessary trace element for most multicellular organisms.