Minerals are naturally-occurring solids with a unique chemical composition and ordered atomic structure, as well as an external form commonly referred to as crystal form.
Some minerals possess intriguing physical characteristics, including their refractive index or how easily light bends when passing through them (brittleness). Others offer useful properties like their ease of cutting or grinding into small pieces (tenacity).
What are minerals?
Minerals are naturally-occurring solid inorganic substances with unique chemical composition and crystal structures, found throughout the world in various rocks.
Mineral formation involves various geological processes. Some minerals form when water evaporates, as in salt flats of lakes and seas or hot springs; they also appear in cracks and fissures in rocks, or precipitated from solutions; or even through living organisms themselves – for instance the aragonite found in shells and pearls is formed this way.
Minerals must possess well-defined, stable chemical composition, with distinct crystalline structures. Homogenous (unable to be physically separated into individual chemical compounds) minerals are the ideal candidate. Even seemingly single substances like rocks may reveal various components when analysed under microscope or through X-ray diffraction analysis; for instance, one rock could contain multiple types of minerals!
How do minerals form?
Minerals form through various geological processes. For instance, some minerals come about due to metamorphic transformations under intense heat and pressure deep within Earth’s crust, changing how its atoms assemble to create new minerals with different physical and chemical properties.
Other minerals form through precipitation from solutions. This occurs when concentrations of dissolved minerals exceed what can be dissolved into solution, leading to precipitation out of solution – for instance halite and calcite are two commonly precipitating minerals found in hot salty lakes such as Utah’s Great Salt Lake.
Most minerals start off their lives as crystalline solids, meaning they possess an ordered internal arrangement of atoms and ions with flat plane surfaces that are regularly shaped – something known as cleavage which serves as one method to classify and identify them.
What are the properties of minerals?
Minerals possess various properties which can be observed and measured. Some common features of minerals include their hardness, cleavage, luster, and streak.
Hardness refers to a mineral’s ability to resist bending, breaking and crushing. Minerals are measured according to Mohs scale of hardness – those which break easily into powder are classified as brittle while those which bend like gold or copper can return back into shape when stressed.
Mineral luster refers to how light is reflected from its surface. A shiny metallic mineral appears silver or gold while matte minerals appear dull. Some minerals have fibrous properties; for instance acicular (needlelike) ulexite in Figure 3.31 exhibits fibers which transmit light, giving it a silky appearance. Some fluorescent minerals light up under ultraviolet or x-ray light while others do not illuminate.
What are the uses of minerals?
Minerals are used in an assortment of products. Metallic minerals like hematite (an iron source), bauxite (an aluminum source), pyrite (fools gold) and galena (a source of lead) are frequently employed to manufacture automobiles, buildings and electricity production equipment.
Nonmetallic minerals have an array of applications. Calcium carbonate, found in sedimentary rock deposits like gypsum and limestone, is used in paper production, plastics manufacturing, rubber manufacturing and fertilizers production as well as being an antacid and medication tablet supplement.
Predicting the future of mineral resources can be tricky due to rapid economic development in large and rapidly emerging nations, whose economies will drive an increase in demand for various minerals. But improving efficiency and substitution may help lower use of rare nonrenewable minerals while recycling can prolong some reserves such as lithium metal from minerals like olivine, dolomite and sphalerite to create batteries used in pacemakers and defibrillator machines.
