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{{short description|Natural springs that produce water containing minerals}}
{{redirect|Sulphur spring|other uses|Sulphur Springs (disambiguation){{!}}Sulphur Springs}}
{{Other uses|Mineral Springs (disambiguation){{!}}Mineral Springs (disambiguation)}}
[[File:Wenceslas Hollar - The mineral spring (State 4).jpg|thumb|210px|right|''The Mineral Spring'', etching by [[Wenceslas Hollar]] (1607–1677). The unidentified central European spring features a sunken stone basin and ornamental retaining wall.]]
[[File:Hot_springs_at_Manikaran,Himachal_Pradesh.jpg|thumb|210px|right|Tourists and pilgrims having a bath in a hot spring in [[Gurudwara]] Complex, [[Manikaran]] in [[Uttrakhand]] state of [[India]], c. May 2009.]]
[[File:Breznik-iron-water-spring.jpg|thumb|180px|right|A chalybeate (iron-laden) mineral spring at [[Breznik]], [[Bulgaria]]]]
[[File:Tap Tapan Mineral Spring.jpg|right|thumb|180px|Tap tapan spring in Azarshahr, Iran]]

'''Mineral springs''' are naturally occurring [[Spring (hydrology)|spring]]s that produce [[hard water]], water that contains dissolved [[mineral]]s. [[Salts]], [[sulfur compounds]], and [[gases]] are among the substances that can be dissolved in the spring water during its passage underground. In this they are unlike [[sweet spring]]s, which produce [[soft water]] with no noticeable dissolved gasses. The dissolved minerals may alter the water's taste. [[Mineral water]] obtained from mineral springs, and the precipitated salts such as [[Magnesium sulfate#Heptahydrate (Epsom salt)|Epsom salt]] have long been important commercial products.

Some mineral springs may contain significant amounts of harmful dissolved minerals, such as [[arsenic]], and should not be drunk.<ref>{{cite web |title=Import Alert 29-02: Detention Without Physical Examination of Bottled Water due to Arsenic Due to Inorganic Arsenic |url=https://www.accessdata.fda.gov/cms_ia/importalert_97.html |archive-url=https://web.archive.org/web/20091008204926/http://www.accessdata.fda.gov/cms_ia/importalert_97.html |url-status=dead |archive-date=October 8, 2009 |website=www.accessdata.fda.gov |publisher=FDA}}</ref><ref>{{cite news |title=Bottled water brand with high levels of arsenic pulled from store shelves |url=https://www.nbcnews.com/health/health-news/bottled-water-brand-found-have-high-levels-arsenic-pulled-stores-n1020991 |publisher=[[NBC News]]}}</ref> Sulfur springs smell of rotten eggs due to [[hydrogen sulfide]] (H<sub>2</sub>S), which is [[Hydrogen sulfide#Safety|hazardous and sometimes deadly]]. It is a gas, and it usually enters the body when it is breathed in.<ref>{{cite web |title=PUBLIC HEALTH STATEMENT: Hydrogen Sulfide |url=https://www.atsdr.cdc.gov/ToxProfiles/tp114-c1-b.pdf |publisher=DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health ServiceAgency for Toxic Substances and Disease Registry, US [[Centers for Disease Control]] |date=December 2016}}</ref> The quantities ingested in drinking water are much lower and are not considered likely to cause harm, but few studies on long-term, low-level exposure have been done, {{as of|lc=yes|2003}}.<ref>{{cite web |title=Hydrogen Sulfide in Drinking-water |url=https://www.who.int/water_sanitation_health/dwq/hydrogensulfide.pdf |publisher=[[World Health Organization]] |date=2003}}</ref>

The water of mineral springs is sometimes claimed to have [[therapeutic]] value. [[Mineral spa]]s are resorts that have developed around mineral springs, where (often wealthy) patrons would repair to "take the waters" — meaning that they would drink (see [[hydrotherapy]] and [[Water cure (therapy)|water cure]]) or bathe in (see [[balneotherapy]]) the mineral water. Historical mineral springs were often outfitted with elaborate stone-works — including artificial pools, [[retaining wall]]s, [[colonnade]]s, and roofs — sometimes in the form of fanciful "Greek temples", [[gazebo]]s, or [[pagoda]]s. Others were entirely enclosed within [[spring house]]s.

==Types==
For many centuries, in Europe, North America, and elsewhere, commercial proponents of mineral springs classified them according to the chemical composition of the water produced and according to the medicinal benefits supposedly accruing from each:

*[[Arsenic|Arsenical springs]] contained arsenic
*[[Lithia water|Lithia Springs]] contained [[lithium salts]].
*[[Chalybeate|Chalybeate springs]] contained salts of [[iron]].
*[[Alum springs]] contained [[alum]].
*Sulfur springs contained [[hydrogen sulfide]] gas (see also [[fumerole]]s).
*[[Salt spring|Salt (saline) spring]]s contained salts of calcium, magnesium or sodium.
*[[Alkaline spring]]s contained an [[alkali]].
*[[Calcic spring]]s contained [[Lime (material)|lime]] ([[calcium hydroxide]]).
*[[Thermal spring|Thermal (hot) spring]]s could contain a high concentration of various minerals.
*[[Soda spring]]s contained [[carbon dioxide]] gas ([[soda water]]).
*[[Radioactive spring]]s contain traces of [[radioactive]] substances such as [[radium]] or [[uranium]].

==Deposits==
[[File:Badab Surt Najafi2.jpg|thumb|180px|right|Stepped [[travertine]] terrace formations at [[Badab-e Surt]], [[Iran]]]]
Types of [[sedimentary rock]] – usually [[limestone]] ([[calcium carbonate]]) – are sometimes formed by the [[evaporation]], or rapid [[Precipitation (meteorology)|precipitation]], of minerals from spring water as it emerges, especially at the mouths of hot mineral springs. In cold mineral springs, the rapid precipitation of minerals results from the reduction of acidity when the {{CO2}} gas bubbles out. (These mineral deposits can also be found in dried lakebeds.) Spectacular formations, including terraces, [[stalactite]]s, [[stalagmite]]s and 'frozen waterfalls' can result (see, for example, [[Mammoth Hot Springs#Mammoth Hot Springs|Mammoth Hot Springs]]).

One light-colored porous [[calcite]] of this type is known as [[travertine]] and has been used extensively in [[Italy]] and elsewhere as building material. Travertine can have a white, tan, or cream-colored appearance and often has a fibrous or concentric 'grain'.

Another type of spring water deposit, containing [[siliceous]] as well as [[calcareous]] minerals, is known as [[tufa]]. Tufa is similar to travertine but is even softer and more porous.

[[Chalybeate|Chaybeate springs]] may deposit iron compounds such as [[limonite]]. Some such deposits were large enough to be [[Chalybeate Spring, Mittagong#Significance|mined as iron ore]].

==See also==
*[[List of hot springs]]
*[[Sweet spring]]s, those with no detectable sulfur or salt content

==References==
{{reflist}}
*Cohen, Stan (Revised 1981 edition), ''Springs of the Virginias: A Pictorial History'', [[Charleston, West Virginia]]: [[Quarrier Press]].
*{{citation |year=2001 |editor1=LaMoreaux, Philip E. |editor2=Tanner, Judy T  |title=Springs and Bottled Water of the World: Ancient History, Source, Occurrence, Quality and use |url=https://books.google.com/books?id=sjEoBmfUka0C&q=springs+bottled |location=Berlin / Heidelberg / New York |publisher=Springer-Verlag |access-date=13 July 2010 |isbn=3-540-61841-4}}

{{AmCyc Poster|Mineral Springs}}
{{Rivers, streams and springs}}
{{Authority control}}

{{DEFAULTSORT:Mineral spring}}
[[Category:Bathing]]
[[Category:Drinking water]]
[[Category:Geomorphology]]
[[Category:Mineral water|*]]
[[Category:Natural environment based therapies]]
[[Category:Spa waters]]
[[Category:Springs (hydrology)]]
[[Category:Water chemistry]]