Everything that is not alive can be called a mineral. A mineral is a chemical element or a combination of chemical elements. They are found nearly everywhere. Minerals are sometimes hard, like iron, gold and basals, or sometimes liquid, such as water, mercury and oil. Mercury is made up of only one element. Water has two: hydrogen and oxygen. Oil is made up of many elements.

What other important minerals are there? Clay, lime, salt, gypsum, copper and silver.... Scientists believe that there are 2000 different kinds of mineral. In certain places, precious minerals can be found which are extracted, if the deposit is economical enough. Some deposits are worked on the surface but on the whole they lie in deep layers which have to be dug out. The word 'ore' is used for all minerals which provide metals. Often-different ores are found in one mine: lead and zinc, for instance. However not all minerals have to mined. Cooking salt comes from the sea, though there are salt mines on the Continent.