A mineral is a solid, naturally formed substance with a definite chemical composition and characteristic crystalline structure. Most minerals are inorganic, but there are a few exceptions.
Minerals are identified by their different properties, and their wide variations in properties allow them be useful in many applications. The principle properties of minerals are color, streak, luster, crystal form, hardness, cleavage, fracture, and density, though other, more specialized properties such as magnetism or scent may be useful too.
Minerals form primarily by the processes of crystallization, metamorphism, precipitation, and hydrothermal solutions.
Minerals can be formed by crystallization of magma (molten rock) deep within a planet. When the magma cools, certain elements combine to form the crystalline structures of minerals. Minerals containing much iron, calcium, and magnesium are often the first to crystallize. As the composition of the magma changes in proportion after the formation of these first minerals, other minerals that are rich in sodium, potassium, ands aluminum.
New minerals can form when immense pressures and temperatures are exerted upon previously existent minerals. When these changes occur, the atoms of thee old minerals are reconfigured to form a more densely packed crystalline structure. Changes in temperature also aid the instability of certain minerals. The new minerals that have been formed must be stable under the new conditions of these pressures and temperatures.
Large bodies of liquid (usually water as its status as a universal solvent) on planets, such as lakes, rivers, or oceans, have often dissolved a great amount of substances. When this liquid evaporates, the substances that had been dissolved are too heavy and are left behind. These substances then form solid minerals. The liquid must not necessarily evaporate, as depending on the solution's properties, a simple change in the liquid's temperature might be enough to engender precipitation.
When some hydrothermal solutions come into contact with present minerals, new chemical reactions occur. These reactions allow new minerals to be formed from the present minerals, and some of the solution can crystalize when it is cooled.
- Mineral compositions of major bodies
- Mineral composition of Mars
- Nelson, Stephen. “Minerals.” Tulane University. 31 August 2015.
- Lutgens, Frederick, and Edward Tarbuck. 2009. Earth Science. Prentice Hall. ISBN 978-0-13-362755-8.