Minerals

MINERALS

Did you ever notice how TV commercials for breakfast cereal always mention vitamins and minerals? But when you think of minerals, food isn't the first thing that comes to mind. Aren't minerals something you find in the earth, like iron and quartz?

Well, yes, but small amounts of some minerals are also in foods. For instance, red meat, such as beef, is a good source of iron.

		A mineral can be defined as a naturally occurring inorganic solid that possesses an orderly internal structure and a definite chemical composition. Some people, like physicists, might be guilty of picking up a rock and calling it a mineral.

The term "rock" is less specific, referring to any solid mass of mineral or mineral-like material. Common rocks are often made up of crystals of several kinds of minerals. There are some substances, like opal, which have the appearance of a mineral but lack any definite internal structure, are sometimes called "mineraloids".