Types of minerals
Minerals make up most of the earth and are an important part of our everyday life.
Minerals are simply naturally occurring substances which have a crystalline structure. There are many thousands of minerals recognised, but only about 30 are most common.
Minerals, being natural chemicals, are classified according to their chemistry and crystal form.
A basic classification for minerals is:
- Native elements. eg. Gold, Silver, Mercury, graphite, diamond.
- Oxides. eg corundum (incl. sapphire), hematite, spinel.
- Hydroxides. eg. Goethite, brucite.
- Sulfides. eg. Pyrite, galena, sphalerite.
- Sulfates. eg. Baryte, gypsum.
- Carbonates. eg. Calcite, magnesite, dolomite.
- Phosphates. eg. Apatite, monazite.
- Halides. eg. Fluorite, halite (rock salt).
- Silicates (most common)
- Orthosilicates. eg. Garnet, olivine.
- Ring silicates. eg. Tourmaline, beryl.
- Chain silicates. eg. Pyroxenes, amphiboles.
- Sheet silicates. eg. Muscovite mica, biotite mica, clay minerals
- Framework silicates. eg. Quartz, feldspars, zeolites
Identifying common minerals can usually be accomplished by examining a hand specimen. Minerals have distinct physical properties such as specific gravity, streak, and form which can easily distinguish the major rock-forming minerals.
More detailed examination of minerals can be undertaken by examining a microscope thin section of a rock or mineral. The optical properties of each mineral are unique, and minerals can be readily identified in thin section. More accurate analysis of minerals can be undertaken with a variety of analytical machines. These include X-ray diffraction, microprobe analysis, mass spectrometry and more. The science of minerals is called Mineralogy.
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