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Descriptive mineralogy

Descriptive mineralogy summarizes results of studies performed on mineral substances. It is the scholarly and scientific method of recording the identification, classification, and categorization of minerals, their properties, and their uses. Classifications for descriptive mineralogy includes:[7] native elements sulfides oxides and hydroxides halides carbonates, nitrates and borates sulfates, chromates, molybdates and tungstates phosphates, arsenates and vanadates silicates organic minerals Mineral classification schemes and their definitions are evolving to match recent advances in mineral science. Recent changes have included the addition of an organic class, in both the new Dana and the Strunz classification schemes.[7][8] The organic class includes a very rare group of minerals with hydrocarbons. The IMA Commission on New Minerals and Mineral Names recently adopted (in 2009) a hierarchical scheme for the naming and classification of mineral groups and group names[9] and established seven commissions and four working groups to review and classify minerals into an official listing of their published names.[10] According to these new rules, "mineral species can be grouped in a number of different ways, on the basis of chemistry, crystal structure, occurrence, association, genetic history, or resource, for example, depending on the purpose to be served by the classification."[9] The Nickel (1995) exclusion of biogenic substances was not universally adhered to. For example, Lowenstam (1981) stated that "organisms are capable of forming a diverse array of minerals, some of which cannot be formed inorganically in the biosphere."[11] The distinction is a matter of classification and less to do with the constituents of the minerals themselves. Skinner (2005) views all solids as potential minerals and includes biominerals in the mineral kingdom, which are those that are created by the metabolic activities of organisms. Skinner expanded the previous definition of a mineral to classify "element or compound, amorphous or crystalline, formed through biogeoc emical processes," as a mineral.[12] Recent advances in high-resolution genetic and x-ray absorption spectroscopy is opening new revelations on the biogeochemical relations between microorganisms and minerals that may make Nickel's (1995)[6] biogenic mineral exclusion obsolete and Skinner's (2005) biogenic mineral inclusion a necessity.[12] For example, the IMA commissioned 'Environmental Mineralogy and Geochemistry Working Group'[13] deals with minerals in the hydrosphere, atmosphere, and biosphere. Mineral forming microorganisms inhabit the areas that this working group deals with. These organisms exist on nearly every rock, soil, and particle surface spanning the globe reaching depths at 1600 metres below the sea floor (possibly further) and 70 kilometres into the stratosphere (possibly entering the mesosphere).[14][15][16] Biologists and geologists have recently started to research and appreciate the magnitude of mineral geoengineering that these creatures are capable of. Bacteria have contributed to the formation of minerals for billions of years and critically define the biogeochemical cycles on this planet. Microorganisms can precipitate metals from solution contributing to the formation of ore deposits in addition to their ability to catalyze mineral dissolution, to respire, precipitate, and form minerals.[17][18][19] Prior to the International Mineralogical Association's listing, over 60 biominerals had been discovered, named, and published.[20] These minerals (a sub-set tabulated in Lowenstam (1981)[11]) are considered minerals proper according to the Skinner (2005) definition.[12] These biominerals are not listed in the International Mineral Association official list of mineral names,[21] however, many of these biomineral representatives are distributed amongst the 78 mineral classes listed in the Dana classification scheme.[12] Another rare class of minerals (primarily biological in origin) include the mineral liquid crystals that are crystalline and liquid at the same time. To date over 80,000 liquid crystalline compounds have been identified.

 
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