Editing Ironstone

{{Short description|Sedimentary rock that contains a substantial proportion of iron ore}}
{{About|the sedimentary rock}}
[[Image:Ironstone_Breathitt.jpg|thumb|300px|Ironstone (sandstone with iron oxides) from the [[Mississippian age|Mississippian]] [[Breathitt Formation]], Mile Marker 166, [[Interstate 64 in Kentucky|I-64]], [[Kentucky]]]]
'''Ironstone''' is a [[sedimentary rock]], either deposited directly as a ferruginous [[sediment]] or created by chemical replacement, that contains a substantial proportion of an [[iron ore]] compound from which [[iron]] (Fe) can be [[smelted]] commercially.

Not to be confused with native or [[telluric iron]], which is very rare and found in metallic form, the term ''ironstone'' is customarily restricted to hard, coarsely banded, non-banded, and non-[[chert]]y sedimentary rocks of [[Phanerozoic|post-Precambrian]] age. The [[Precambrian]] deposits, which have a different origin, are generally known as [[banded iron formation]]s. The iron minerals comprising ironstones can consist either of oxides, i.e. [[limonite]], [[hematite]], and [[magnetite]]; carbonates, i.e. [[siderite]]; silicates, i.e. [[chamosite]]; or some combination of these minerals.<ref name="U.S.BureauofMines1996a">U.S. Bureau of Mines Staff (1996) ''Dictionary of Mining, Mineral, & Related Terms.'' Report SP-96-1, U.S. Department of Interior, U.S. Bureau of Mines, Washington, D.C.</ref><ref name="NeuendorfOthers2005a">Neuendorf, K. K. E., J. P. Mehl Jr., and J. A. Jackson, J. A., eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. {{ISBN|0-922152-76-4}}</ref>

==Description==
Freshly cleaved ironstone is usually grey. The brown external appearance is due to [[oxidation]] of its surface.
Ironstone, being a sedimentary rock is not always [[homogeneous]], and can be found in a red-and-black banded form called [[Tiger's eye#Tiger iron|tiger iron]]{{Broken anchor|date=2024-06-25|bot=User:Cewbot/log/20201008/configuration|target_link=Tiger's eye#Tiger iron|reason= The anchor (Tiger iron) [[Special:Diff/800258713|has been deleted]].}}, sometimes used for [[jewelry]] purposes.

Sometimes ironstone hosts [[concretion]]s or [[opal]] gems.

==Occurrence==
Ironstone occurs in a variety of forms. The various forms of ironstone include siderite nodules; deeply weathered [[saprolite]], i.e. ([[laterite]]); and [[Oolite|ooidal]] ironstone.

==Uses==
===Ironstone as a source of iron===
Ironstone, although widespread, is a limited source of iron. Historically, most British iron originated from ironstone, but it is now rarely used for this purpose because it is far too limited in quantity to be an economic source of iron ore.

===Ceramics===
Ironstone's oxide impurities render it useless as a component in [[ceramic]]s: the "[[ironstone china]]" of Staffordshire and American manufacture, a fine, white, high-fired vitreous [[semi-porcelain]], commonly used for heavy-duty dinner services in the 19th century,<ref>G. Bernard Hughes, ''English and Scottish Earthenware'', Abbey Library</ref> includes no ironstone in its production. Its "iron" quality is in its resistance to chipping.

===In construction===
[[File:Ironstone wall - geograph.org.uk - 5264087.jpg|thumb|Ironstone wall in [[Deddington]]]]
The stone can be used as a building material. Examples include the [[parish church]]es at [[Kirby Bellars]] and [[South Croxton]] in [[Leicestershire]], and [[Eydon Hall]] in [[Northamptonshire]].

===In art===
Sculptures carved out of ironstone are rare. One example is [[Henry Moore]]'s ''Head'' created in 1930.<ref>{{Cite web |date=22 November 2023 |title=Henry Moore O.M., C.H. (British, 1898-1986) |url=https://www.bonhams.com/auction/28543/lot/23P/henry-moore-om-ch-british-1898-1986-head-177-cm-7-in-high-including-the-marble-base-carved-in-1930-unique |access-date=5 December 2023 |website=bonhams.com}}</ref>

==See also==
* [[Iron ore]]
* [[Iron-rich sedimentary rocks]]
* [[Ironsand]]

==References==
{{Commons category|Ironstone}}
{{Reflist}}

{{Authority control}}

[[Category:Sedimentary rocks]]
[[Category:Iron ores]]