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{{short description|Cultural or commercial name for a number of dimension or building stone varieties}}
{{about|various "blue" building stones}}
{{distinguish|Copper(II) sulfate}}
{{More citations needed|date=April 2008}}
{{Use dmy dates|date=April 2025}}
[[File:Carn Menyn bluestones - geograph.org.uk - 1451509.jpg|thumb|right|upright=1.4|[[Carn Menyn]] bluestones. These dolerite slabs, split by frost action, seem to be stacked ready for the taking, and many have been removed over the centuries for local use. Research favours the theory that humans also transported stones from Carn Menyn to build [[Stonehenge]], about 250{{nbsp}}km away.]]

'''Bluestone''' is a cultural or commercial name for a number of natural [[dimension stone|dimension]] or building stone varieties, including:

* [[basalt]] in [[Victoria (Australia)|Victoria]], Australia, and in New Zealand
* [[diabase|dolerite]]s in [[Tasmania]], Australia; and in Britain (including [[Stonehenge]])
* [[feldspar|feldspathic]] [[sandstone]] in the US and Canada 
* [[limestone]] in the [[Shenandoah Valley]] in the US, from the [[Hainaut (province)|Hainaut]] quarries in [[Soignies]], Belgium, and from quarries in [[County Carlow]], [[County Galway]] and [[County Kilkenny]] in Ireland
* [[slate]] in [[South Australia]]
It is unrelated to human-made [[blue brick]].

==Stonehenge==
[[File:Carnmenyn Monument H1a.jpg|thumb|Bluestone monument and Carn Menyn, [[Preseli Hills]]]]

The term "bluestone" in Britain is used in a loose sense to cover all of the "foreign", not intrinsic, stones and rock debris at [[Stonehenge]]. It is a "convenience" label rather than a geological term, since at least 46 different rock types are represented. One of the most common rocks in the assemblage is known as Preseli spotted [[dolerite]]—a chemically altered [[igneous rock]] containing spots or clusters of secondary minerals replacing [[plagioclase]] [[feldspar]]. It is a medium grained dark and heavy rock, harder than granite. 

Preseli bluestone tools, such as axes, have been discovered elsewhere within the British Isles. Many of them appear to have been made in or near Stonehenge, since there are petrographic similarities with some of the spotted dolerites there. The bluestones at [[Stonehenge]] were first used there during the third phase of construction at Stonehenge around 2300 BC.<ref>{{cite web |last = Swaine| first =Jon| title =Stonehenge birthdate discovered by archaeologists| work =[[The Daily Telegraph]]| date=2008-09-22| url =https://www.telegraph.co.uk/news/3046095/Stonehenge-birthdate-discovered-by-archaeologists.html | access-date =2008-09-22}}</ref> It is assumed that there were about 80 monoliths originally, but this has never been proven since only 43 remain. The stones are estimated to weigh between 2 and 4 tons each. The majority of them are believed to have come from the [[Preseli Hills]], about {{convert|250|km|mi}} away in [[Wales]], either through [[glaciation]] ([[glacial erratic]] theory) or through humans organizing their transportation.

===Glacial erratic theory===
A summary of the major aspects of the Stonehenge "bluestone conundrum" was published in 2008.<ref>{{cite book |first=Anthony |last=Johnson |title=Solving Stonehenge: The New Key to an Ancient Enigma |at=fig. 89, p. 165 |publisher=Thames and Hudson |year=2008 |isbn=978-0-500-05155-9}}</ref> In 2018 a book devoted specifically to the problem of bluestone provenance and transport concluded that the Stonehenge bluestones are essentially an ill-sorted assemblage of glacial erratics.<ref>{{cite book |first=Brian |last=John |title=The Stonehenge Bluestones |publisher=Greencroft Books |year=2018 |page=157 |ISBN=978-0-905559-94-0}}</ref> Much further research into the origin of the bluestones has been published between 2012 and 2022 particularly by geologists Richard Bevins and Rob Ixer.<ref>{{cite journal |last1=Bevins |first1=Richard E. |last2=Ixer |first2=Rob A. |last3=Webb |first3=Peter C. |last4=Watson |first4=John S. |title=Provenancing the rhyolitic and dacitic components of the stonehenge landscape bluestone lithology: New petrographical and geochemical evidence |journal=Journal of Archaeological Science |volume=39 |issue=4 |date=April 2012 |pages=1005–1019}}</ref> If a glacier transported the stones, then it must have been the [[Irish Sea Glacier]].<ref>{{cite journal |vauthors=Chiverrekk RC, Thrasher I, Thomas GS, Lang A, et al |year=2013 |title=Bayesian modelling the retreat of the Irish Sea Ice Stream |journal=Journal of Quaternary Science |volume=28 |issue=2 |pages=200–209}}</ref> In support of the [[glacial erratic]] theory, researchers reporting in 2015 found no firm evidence of quarrying at Rhosyfelin in the Preselis.<ref>{{cite news|work=Western Telegraph|title=New research undermines Welsh bluestone quarry theory|date=13 November 2015 |url=http://www.westerntelegraph.co.uk/news/14030126.New_research_undermines_Welsh_bluestone_quarry_theory/|access-date=13 November 2015}}</ref> However, in such event, one might expect to find other bluestone boulders or slabs near the Stonehenge site, but no such bluestones (apart from fragments) have been found.<ref>{{cite episode |network=National Geographic Channel |series=Naked Science |title=Who Built Stonehenge? |date=October 6, 2004<!--from [[List of Naked Science episodes]]--> |url=http://channel.nationalgeographic.com/channel/episodes/who-built-stonehenge/ |url-status=dead |archive-url=https://web.archive.org/web/20130502033832/http://channel.nationalgeographic.com/channel/episodes/who-built-stonehenge/ |archive-date=May 2, 2013 }}</ref>

===Human transport theory===
The archaeological find of the [[Boscombe Bowmen]] has been cited in support of the human transport theory. Preseli Bluestone dolerite axe heads have been found around the [[Preseli Mountains|Preseli Hills]] as well, indicating that there was a population who knew how to work with the stones,<ref>{{cite book |first=N. P. |last=Figgis |author-link=N. P. Figgis |title=Prehistoric Preseli |publisher=Atelier Productions |year=2001 |isbn=1-899793-06-2}}{{page needed|date=June 2013}}</ref> In 2015, researchers claimed that some of the stones at Stonehenge came from Neolithic quarries at Carn Goedog and [[Craig Rhos-y-felin]] in the Preseli Hills.<ref>{{cite news|publisher=University College London|title=Stonehenge 'bluestone' quarries confirmed 140 miles away in Wales|date=7 December 2015|url=http://www.ucl.ac.uk/news/news-articles/1215/071215-stonehenge-bluestone-quarries|access-date=3 August 2018}}</ref> The quarrying hypothesis has been hotly disputed by Brian John, Dyfed Elis-Gruffydd and John Downes, whose own detailed research led to the conclusion that the so-called quarrying features were all natural, created over a long period of glacial and periglacial landscape change.<ref>{{cite journal |first1=Brian |last1=John |first2=Dyfed |last2=Elis-Gruffydd |first3=John |last3=Downes |year=2015 |title=Observations on the supposed 'Neolithic bluestone quarry' at Craig Rhosyfelin, Pembrokeshire |journal=Archaeology in Wales |volume=54 |pages=139–148}}</ref> Further, no independent evidence has ever been found to support the thesis of long overland or sea transport of Preseli bluestones from Wales to Salisbury Plain.

==Australia==
[[Image:Pentridge.jpg|thumb|upright|HM Prison Pentridge was one of the many buildings constructed of local bluestone in Melbourne in the 19th century]]

There are three distinct building materials called "bluestone" in Australia.

===Victoria ===
In [[Victoria (Australia)|Victoria]], what is known as bluestone is a basalt or [[olivine]] basalt. It was one of the favoured building materials during the [[Victorian Gold Rush]] period of the 1850s. In [[Melbourne]], it was extracted from quarries throughout the inner northern suburbs, such as [[Clifton Hill, Victoria|Clifton Hill]], [[Brunswick, Victoria|Brunswick]] and [[Coburg, Victoria|Coburg]], where the quarry used to source the stone for [[HM Prison Pentridge|Pentridge Prison]] is now Coburg Lake.<ref>History of Brunswick, City of Moreland, http://moreland.vic.gov.au/moreland-libraries/services/local-history/history-brunswick.html {{Webarchive|url=https://web.archive.org/web/20110328164911/http://www.moreland.vic.gov.au/moreland-libraries/services/local-history/history-brunswick.html |date=2011-03-28 }}, accessed 11 September 2012</ref><ref>''Encyclopedia of Melbourne'': Quarries and Brickmaking, http://www.emelbourne.net.au/biogs/EM01213b.htm, accessed 11 September 2012</ref> Bluestone was also sourced in many other regions of the Victorian volcanic plains, and used in towns and cities in the state's central and western regions, including [[Ballarat]], [[Geelong]], [[Kyneton]], [[Port Fairy]] and [[Portland, Victoria|Portland]]. It is still quarried at a number of places around the state.

Bluestone is a very hard material and therefore difficult to work, so it was predominantly used for warehouses, miscellaneous walls, and the foundations of buildings. However, a number of significant bluestone buildings exist, including the [[Old Melbourne Gaol]], [[HM Prison Pentridge|Pentridge Prison]], [[St Patrick's Cathedral, Melbourne|St Patrick's Cathedral]], [[Victoria Barracks, Melbourne|Victoria Barracks]], [[Melbourne Grammar School]], [[Deaf Children Australia]] and [[Victorian College for the Deaf]], [[Royal Victorian Institute for the Blind|Vision Australia]], the [[Goldsbrough Mort & Co.|Goldsbrough Mort]] warehouses ([[Bourke Street, Melbourne|Bourke Street]]) and the [[Williamstown Lighthouse|Timeball Tower]] at [[Williamstown, Victoria|Williamstown]], as well as [[St Mary of the Angels Basilica, Geelong|St Mary's Basilica]] in [[Geelong]]. Some examples of other major structures that use bluestone include [[Princes Bridge, Melbourne|Princes Bridge]], the adjacent Federation Wharf, and [[Hawthorn Bridge]]. Because of its distinctive qualities, [[postmodern architecture|post-modern]] Melbourne buildings have also made use of bluestone for nostalgic reasons. They include the Southgate complex and the promenade in [[Southbank, Victoria]].

Bluestone was used extensively as [[cobblestone]], and for kerbs and gutters, many examples of which still exist in Melbourne's smaller city lanes, and 19th-century inner-suburban streets and lanes. Crushed bluestone [[construction aggregate|aggregate]], known as "blue metal" (or "bluemetal"), is used extensively in Victoria as railway [[track ballast|ballast]], as [[base course|road base]], and in making concrete. Combined with [[bitumen]], it is used as a road surfacing material.

===South Australia===
[[Image:Bluestone33.jpg|thumb|right|Typical colouring caused by mineralisation in Adelaide bluestone]]

In [[South Australia]], the name bluestone is given to a form of [[slate]] which is much less durable than Victorian bluestone, but was valued for its decorative appearance.  The interior of the stone is usually pale grey or beige in colour, but is given attractively coloured surfaces by ferric oxide and other minerals deposited in joints and bedding planes.  The slate is laid in masonry with the mineralised surfaces exposed.  Bluestone was most popular from about the 1850s to the 1920s, quarried in the [[Adelaide Hills]] at [[Dry Creek, South Australia|Dry Creek]], [[O'Halloran Hill]] (formerly Tapley's Hill) and [[Glen Osmond]], as well as a number of other places in rural areas.<ref>R. Lockhart Jack, "The Building Stones of South Australia" (Adelaide 1923) pp. 18-28.</ref>

===Tasmania===
In Tasmania, the name bluestone is given to dolerite (diabase), which is a dominant stone variety in the landscape, and used in a variety of building roles.<ref>{{cite web|title=Building Stone|url=http://www.utas.edu.au/library/companion_to_tasmanian_history/B/Building%20stone.htm|website=Companion to Tasmanian History|access-date=18 May 2017}}</ref>

==New Zealand==
[[File:Dunedin Railway Station and Dunedin Law Courts.jpg|thumb|right|Dunedin Railway Station and Law Courts, New Zealand, showing dark bluestone and creamy Oamaru stone construction]]

[[Timaru]] bluestone (also known as [[Port Chalmers]] bluestone) is an attractive building material, used both historically and to the present. It is a grey basalt similar to Victorian bluestone, quarried near Timaru in the South Island. Bluestone from near Kokonga in [[Central Otago]] is also widely used, and is the main construction material (often with facing of [[Oamaru stone]], a local compact limestone) in many of the notable historic buildings in the southern South Island, most of which were constructed during the financial boom following the [[Otago gold rush]]. Prominent structures to use this combination include [[Otago University Registry Building]], [[Dunedin Law Courts]], and [[Dunedin Railway Station]]. Similar construction using Timaru bluestone was used for [[Christchurch Arts Centre]].

==United States and Canada==
[[File:Starrucca Viaduct, Oct 2014.jpg|thumb|[[Starrucca Viaduct]], Pennsylvania]]
There are two distinct building materials called "bluestone" in the United States, one of which is also found in Canada.

Bluestone from [[Pennsylvania]] and [[New York (state)|New York]] is a [[sandstone]] defined as [[Feldspar|feldspathic]] [[greywacke]]. The sand-sized grains from which bluestone is constituted were deposited in the [[Catskill Delta]] during the Middle to Upper [[Devonian Period]] of the [[Paleozoic Era]], approximately 370 to 345 million years ago. The Catskill Delta was created from runoff from the [[Acadian Mountains]] ("Ancestral Appalachians").<ref>{{cite journal|last=Ettensohn|first=F|title=The Catskill Delta complex and the Acadian Orogeny|journal=The Catskill Delta. Geological Society of America|year=1985|series=39-49|doi=10.1130/SPE201-p39}}</ref> This delta ran in a narrow band from southwest to northeast and today provides the bluestone quarried from the [[Catskill Mountains]] and [[Northeastern Pennsylvania]]. The term "bluestone" is derived from a deep-blue-colored sandstone first found in [[Ulster County, New York]].<ref>{{Cite web|url=https://pages.vassar.edu/hudsonvalleyguidebook/2013/06/03/bluestone-quarries/|title=Bluestone Quarries {{!}} Welcome to the Hudson Valley: A Guidebook of Topics in Local Environmental History|last=Mahayes|language=en-US|access-date=2019-10-23}}</ref> It can, however, appear in many other hues, mostly shades of grays and browns. Bluestone quarrying is of particular value to the economy of [[Susquehanna County, Pennsylvania]]. The [[Starrucca Viaduct]], finished in 1848, is an example of Pennsylvania bluestone as a building material.<ref name=SusCounty/> Bluestone is quarried in western New Jersey, Pennsylvania, and eastern New York.<ref>{{Cite book |url=https://books.google.com/books?id=2K8rqyKwUP8C&q=bluestone%2520is%2520a%2520feldspathic%2520%255B%255Bsandstone%255D%255D%252C%2520which%2520is%2520produced%2520in%2520hundreds%2520of%2520small%2520quarries%2520in%2520adjacent%2520areas%2520of%2520Pennsylvania%2520and%2520New%2520York&pg=PA202 |title=Architectural Stone: Fabrication, Installation, and Selection |last=Chacon |first=Mark A. |date=1999-10-11 |publisher=John Wiley & Sons |language=en |access-date=2019-01-31|isbn=9780471246596 }}</ref> It is also quarried in the Canadian Appalachians near Deer Lake in Western Newfoundland.<ref>{{cite web |url=https://www.nr.gov.nl.ca/nr/mines/geoscience/publications/of_nfld2865.pdf |title=Dimension Stone in Newfoundland and Labrador |last1=Evans |first1=DT |last2=Dickson |first2=WL |date=2004 |website=Government of Newfoundland and Labrador |access-date=25 January 2019}}</ref> The Pennsylvania Bluestone Association has 105 members, the vast majority of them quarriers.<ref name=SusCounty>{{cite web |url=http://susqco.com/economic-development/pennsylvania-bluestone/ |title=Susquehanna County: The Heart of Pennsylvania Bluestone |website=Susquehanna County, Pennsylvania |access-date=25 January 2019}}</ref> 

The other, lesser known, type of American "bluestone" is a blue-tinted [[limestone]] abundant in the [[Shenandoah Valley]] of [[Virginia]]. It is a limestone formed during the [[Ordovician]] Period approximately 450 to 500 million years ago, at the bottom of a relatively shallow ocean that covered what is today [[Rockingham County, Virginia]]. The limestone that accumulated there was darker in color than most other limestone deposits because it was in deeper waters exposed to less light. The darker blue color resulted in limestone from this region being dubbed "bluestone" and with two sequences measuring about {{convert|10,000|ft}} thick, it gives the area one of the largest limestone deposits in the world.<ref>{{cite web |url=http://csmres.jmu.edu/geollab/vageol/outreach/fieldtrips/rockingham/whole.html  |title=A Brief Geologic History of Rockingham County |last=Sherwood |first=WC |website=James Madison University |access-date=25 January 2019}}</ref> The stone eventually fades from a deep blue to a light grey after prolonged exposure to sun and rain. Given the abundance of the stone in the Rockingham County area, the first settlers used it as foundations and chimneys for their houses. When [[James Madison University]] was built, the local bluestone was used to construct the buildings because of its high quality and cultural heritage.<ref>{{cite web |url=http://www.jmu.edu/centennialcelebration/bluestone.shtml |title=JMU Centennial Celebration - The History of Bluestone |date=2007 |website=James Madison University |access-date=26 January 2019}}</ref>

==See also==
*[[Theories about Stonehenge]]

==References==
{{Reflist}}

==Bibliography==
* Jack, R Lockhart. ''The Building Stones of South Australia''. Bulletin No. 10, Geological Survey of South Australia, Adelaide, 1923.
* John, Brian. ''The Bluestone Enigma: Stonehenge, Preseli and the Ice Age''.  Greencroft Books, 2008, page 95.  {{ISBN|978-0-905559-89-6}}.
* Jones, Nancy. ''Rooted on Bluestone Hill: A History of James Madison University''. Center for American Places, Inc. Santa Fe, NM. 2004.

==External links==
{{Commonscat|Bluestones}}
*[https://web.archive.org/web/20150214203942/http://brianjohn.info/bluestones59.html Examination of the conflicting theories relating to the Stonehenge bluestones]
*[https://web.archive.org/web/20140811011622/http://www.brianjohn.info/bluestonesimp58.html Enigma of the Stonehenge Bluestones and the Preseli Hills]
*[http://www.wessexarch.co.uk/projects/wiltshire/boscombe/bowmen/stonehenge_bluestones.html  Wessex Archaeology's Bluestone information]
*[https://web.archive.org/web/20080716053344/http://www.britannia.com/history/preseli_blue.html Secrets of the Preseli Bluestones]
*[https://news.bbc.co.uk/2/hi/science/nature/7625145.stm Dig Pinpoints Stonehenge Origins]
*[http://quarriesandbeyond.org/articles_and_books/pdf/bluestone_sidewalks_scientific_american_november_22_1890.pdf "Bluestone Sidewalks"] (Bluestone quarried in the state of New York), ''Scientific American'', Vol. LXIII, No. 21, New York, November 22, 1890

[[Category:Building stone]]
[[Category:Basalt]]
[[Category:Stone (material)]]
[[Category:Industrial minerals]]
[[Category:Limestone]]
[[Category:Slate]]