View source for Earth:Mineral spring

{{short description|Natural springs that produce water containing minerals}}
[[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 {{wipe|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 [[Earth:Spring (hydrology)|spring]]s that produce [[Physics:Hard water|hard water]], water that contains dissolved [[Earth:Mineral|mineral]]s. Salts, [[Chemistry:Sulfur compounds|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 springs, which produce [[Chemistry:Soft water|soft water]] with no noticeable dissolved gasses. The dissolved minerals may alter the water's taste. [[Chemistry:Mineral water|Mineral water]] obtained from mineral springs, and the precipitated salts such as [[Chemistry: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 [[Chemistry:Arsenic|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 |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 [[Chemistry:Hydrogen sulfide|hydrogen sulfide]] (H<sub>2</sub>S), which is [[Chemistry: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=[[Organization:World Health Organization|World Health Organization]] |date=2003}}</ref>

The water of mineral springs is sometimes claimed to have therapeutic value. Mineral spas are resorts that have developed around mineral springs, where (often wealthy) patrons would repair to 'take the waters' — meaning that they would drink (see [[Unsolved:Hydrotherapy|hydrotherapy]] and water cure) or bathe in (see [[Medicine:Balneotherapy|balneotherapy]]) the mineral water. Historical mineral springs were often outfitted with elaborate stone-works — including artificial pools, [[Engineering:Retaining wall|retaining wall]]s, [[Engineering:Colonnade|colonnade]]s and roofs — sometimes in the form of fanciful 'Greek temples', gazebos or [[Engineering:Pagoda|pagoda]]s. Others were entirely enclosed within [[Physics:Spring house|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:

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

==Deposits==
[[File:Badab Surt Najafi2.jpg|thumb|180px|right|Stepped travertine terrace formations at Badab-e Surt, Iran]]
Types of [[Earth:Sedimentary rock|sedimentary rock]] – usually [[Earth:Limestone|limestone]] ([[Chemistry:Calcium carbonate|calcium carbonate]]) – are sometimes formed by the [[Physics:Evaporation|evaporation]], or rapid 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, stalactites, stalagmites and 'frozen waterfalls' can result (see, for example, Mammoth Hot Springs).

One light-colored porous [[Chemistry:Calcite|calcite]] of this type is known as [[Earth:Travertine|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 [[Earth:Calcareous|calcareous]] minerals, is known as [[Earth:Tufa|tufa]]. Tufa is similar to travertine but is even softer and more porous.

[[Chemistry:Chalybeate|Chaybeate springs]] may deposit iron compounds such as [[Chemistry:Limonite|limonite]]. Some such deposits were large enough to be mined as iron ore.

==See also==
*List of hot springs
*Sweet springs, 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}}

{{DEFAULTSORT:Mineral spring}}
[[Category:Geomorphology]]
[[Category:Mineral water|*]]
[[Category:Water chemistry]]

{{Sourceattribution|Mineral spring}}