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Revision as of 06:34, 20 June 2002
Minerals are natural compounds formed through geological processes. They can be compared to rocks, which are usually mixtures of several different minerals. These range in composition from elements and simple salts to very complex silicates (with most organic compounds usually excluded), with thousands of known forms. To be classified as a true mineral, a substance must be a solid and have a crystal structure. Mineral-like substances that don't strictly meet the definition are sometimes classified as mineraloids. The study of minerals is called mineralogy.
http://meta.wikipedia.com/upload/minerals.jpg
Photo from US Geological Survey
Some important rock-forming minerals include the feldspars, quartz, olivines, pyroxenes, garnets, micas, and calcite. Other well-known minerals include the wide variety of gemstones. Trying to list all the minerals here would probably be counter-productive; maybe they can be linked from their chemical compositions (eg Silicon dioxide->Quartz, Chalcedony, Opal)?
Minerals in respect to nutrition refers to inorganic compounds necessary for life. Some of these are scientific minerals as salt; others are elements, as potassium, calcium, iron, zinc, magnesium, copper. These can be naturally occuring in food or added in elemental or mineral form to food, as calcium carbonate, iron fillings, etc. Some of these additives are from natural sources as ground oyster shells for calcium carbonate. Sometimes minerals are added to the diet separately from food, as vitamin and mineral supplements and in dirt eating, called pica or geophagy.
The physical hardness of a mineral is usually measured on the Mohs scale of mineral hardness.