Secondary raw materials and metals have been known for thousands of years.  Metals are a precious raw material. We can also notice that many items for everyday use are actually made of metal. Some metals have been used for thousands of years, for instance copper and iron. Metals are found in ore, which is a compound that contains a high share of metal. Only some metals, for example copper, are found in the earth’s crust as pure metals. Unfortunately, those are becoming rarer and rarer in the nature. If rare metals happen to be completely exploited some day, we will have to find a replacement for those. Otherwise people possessing them will determine their value.