Editing Mineral (section)

===International Mineralogical Association===
The [[International Mineralogical Association]] has established the following requirements for a substance to be considered a distinct mineral:<ref name=nick1998>E. H. Nickel & J. D. Grice (1998): "The IMA Commission on New Minerals and Mineral Names: procedures and guidelines on mineral nomenclature". ''Mineralogy and Petrology'', volume 64, issue 1, pages 237–263. {{doi|10.1007/BF01226571}}</ref><ref name=Nickel>{{cite journal |last = Nickel |first = Ernest H. |title = The definition of a mineral |journal = The Canadian Mineralogist |volume = 33 |issue = 3 |pages = 689–90 |date = 1995 |url = https://pubs.geoscienceworld.org/canmin/article-abstract/33/3/689/12679/the-definition-of-a-mineral?redirectedFrom=fulltext |access-date = 2018-04-04 |archive-date = 2018-08-25 |archive-url = https://web.archive.org/web/20180825002651/https://pubs.geoscienceworld.org/canmin/article-abstract/33/3/689/12679/the-definition-of-a-mineral?redirectedFrom=fulltext |url-status = live }}</ref>

# ''It must be a naturally occurring substance formed by natural geological processes'', on Earth or other extraterrestrial bodies.  This excludes compounds directly and exclusively generated by human activities ([[wikt:anthropogenic|anthropogenic]]) or in living beings ([[wikt:biogenic|biogenic]]), such as [[tungsten carbide]], [[kidney stone disease|urinary calculi]], [[calcium oxalate]] crystals in plant tissues, and [[seashell]]s.  However, substances with such origins may qualify if geological processes were involved in their genesis (as is the case of [[evenkite]], derived from plant material; or [[taranakite]], from [[bat guano]]; or [[alpersite]], from mine tailings).<ref name=Nickel /> Hypothetical substances are also excluded, even if they are predicted to occur in inaccessible natural environments like the Earth's core or other planets.
# ''It must be a solid substance in its natural occurrence.''  A major exception to this rule is native [[mercury (element)|mercury]]: it is still classified as a mineral by the IMA, even though crystallizes only below −39&nbsp;°C, because it was included before the current rules were established.<ref>{{cite web |url=https://www.mindat.org/min-2647.html |title=Mercury |publisher=Mindat.org |access-date=3 April 2018 |archive-date=7 January 2018 |archive-url=https://web.archive.org/web/20180107110532/https://www.mindat.org/min-2647.html |url-status=live }}</ref>  Water and [[carbon dioxide]] are not considered minerals, even though they are often found as [[inclusion (mineral)|inclusions]] in other minerals; but [[Ice|water ice]] is considered a mineral.<ref>{{cite web |url=https://www.mindat.org/min-2001.html |title=Ice |publisher=Mindat.org |access-date=3 April 2018 |archive-date=4 June 2020 |archive-url=https://web.archive.org/web/20200604131947/https://www.mindat.org/min-2001.html |url-status=live }}</ref>
# ''It must have  a well-defined crystallographic structure''; or, more generally, an ordered atomic arrangement.<ref name="DG2_4" /> This property implies several [[macroscopic scale|macroscopic]] physical properties, such as crystal form, hardness, and cleavage.<ref name="CL13-14">{{harvnb|Chesterman|Lowe|2008}}, pp. 13–14</ref> It excludes [[ozokerite]], [[limonite]], [[obsidian]] and many other amorphous (non-crystalline) materials that occur in geologic contexts.
# ''It must have a fairly well defined chemical composition''. However, certain crystalline substances with a fixed structure but variable composition may be considered single mineral species.  A common class of examples are [[solid solution]]s such as [[mackinawite]], (Fe, Ni)<sub>9</sub>S<sub>8</sub>, which is mostly a [[iron|ferrous]] sulfide with a significant fraction of iron atoms replaced by [[nickel]] atoms.<ref name="DG2_4" /><ref>{{cite web|url=https://www.mindat.org/min-2512.html|title=Mackinawite|publisher=Mindat.org|access-date=3 April 2018|archive-date=3 January 2019|archive-url=https://web.archive.org/web/20190103005122/https://www.mindat.org/min-2512.html|url-status=live}}</ref> Other examples include layered crystals with variable layer stacking, or crystals that differ only in the regular arrangement of [[Vacancy defect|vacancies]] and substitutions. On the other hand, some substances that have a continuous series of compositions, may be arbitrarily split into several minerals. The typical example is the [[olivine]] group (Mg, Fe)<sub>2</sub>SiO<sub>4</sub>, whose magnesium-rich and iron-rich end-members are considered separate minerals ([[forsterite]] and [[fayalite]]).

The details of these rules are somewhat controversial.<ref name="DG2_4" /> For instance, there have been several recent proposals to classify amorphous substances as minerals, but they have not been accepted by the IMA.

The IMA is also reluctant to accept minerals that occur naturally only in the form of [[nanoparticle]]s a few hundred atoms across, but has not defined a minimum crystal size.<ref name=nick1998/>

Some authors require the material to be a [[thermodynamic stability|stable or metastable]] solid at [[room temperature]] (25&nbsp;°C).<ref name="DG2_4">{{Cite book|title = Mineralogy and Optical Mineralogy |author=Melinda Darby Dyar |author2=Mickey E. Gunter |publisher = Mineralogical Society of America|year = 2007|isbn = 978-0-939950-81-2|pages = 2–4}}</ref>  However, the IMA only requires that the substance be stable enough for its structure and composition to be well-determined. For example, it recognizes [[meridianiite]] (a naturally occurring hydrate of [[magnesium sulfate]]) as a mineral, even though it is formed and stable only below 2&nbsp;°C.

{{As of|2025|03}}, 6,126 mineral species are approved by the IMA.<ref name="IMAMineralsCount"/> They are most commonly [[List of minerals named after people|named after a person]], followed by discovery location; names based on chemical composition or physical properties are the two other major groups of mineral name etymologies.<ref name="DG20-22"/><ref>{{harvnb|Dyar|Gunter|2008}}, p. 556</ref>  Most names end in "-ite"; the exceptions are usually names that were well-established before the organization of mineralogy as a discipline, for example [[galena]] and [[diamond]].