quartzolite
{{distinguish|quartzite|silex}}
{{Short description|Extremely rare igneous rock made mostly of quartz}}
File:Qapf diagram plutonic 05.svg of the QAPF diagram for plutonic rocks]]
Quartzolite or silexite is an intrusive igneous rock, in which the mineral quartz is more than 90% of the rock's felsic mineral content, with feldspar at up to 10%.{{cite book | title=Igneous Rocks:A Classification and Glossary of Terms | publisher=Cambridge University Press | editor=Le Maitre, R. W. | year=2002 | location=Cambridge | isbn=978-0-521-66215-4| edition=2nd }}{{Rp|135}}{{cite web | url=http://www.bgs.ac.uk/bgsrcs/rcs_details.cfm?code=QTZOLT | title=Quartzolite | publisher=British Geological Survey | work=BGS Rock Classification Scheme | access-date=20 November 2016}} Typically, quartz forms more than 60% of the rock,{{cite web | url=http://www.mindat.org/glossary/silexite | title=Definition of silexite | publisher=mindat.org | access-date=20 November 2016}} the rest being mostly feldspar although minor amounts of mica or amphibole may also be present. Quartzolite occurs as dykes, sills, veins, bosses and segregation masses;{{cite journal | url=http://digsopen.minerals.nsw.gov.au/?rin=R00040849 | title=The Torrington silexite deposits | author=Lishmund, S.R. | journal=Geological Survey of New South Wales: Quarterly Notes | year=1974 | volume=17 | pages=3–6}} it is also found in association with greisen and pegmatite.{{cite web | url=http://www.nr.gov.nl.ca/nr/mines/prospector/matty_mitchell/pdf/Mo-Sb-W/Ackley.pdf | title=Ackley Mo-Sn-F-W | publisher=Matty Mitchell Prospectors Resource Room | work=Newfoundland & Labrador: Explore The Opportunities | date=2013 | access-date=21 November 2016 | author=Fraser, Dean}}{{cite journal | url=http://www.geology.cz/img/zpravyvyzkum/fulltext/zpravy-o-vyzkumech-2003-str-112-114.pdf | journal=Zprávy o geologických výzkumech v roce | title=Topazový Kvarcolit (Greisen) u Chrastavy v Severních Čechách Jako Metalogenetický Indikátor W-Sn Mineralizace | trans-title=Topaz quartzolite (greisen) near Chrastava in Northern Bohemia – metallogenic indicator of the W-Sn mineralization | first1=Josef | last1=Klominsky | first2=Ferry | last2=Fediuk | first3=Frantisek | last3=Veselovsky | first4=Pavel | last4=Schovanek | first5=Tomas | last5=Jarchovsky | first6=Zdenìk | last6=Taborsky | language=cs | year=2003 | pages=112–114 | issn=0514-8057}}{{cite journal | title=Britholite Group Minerals from REE-Rich Lithologies of Keivy Alkali Granite—Nepheline Syenite Complex, Kola Peninsula, NW Russia | first1=D. | last1=Zozulya | first2=L. | last2=Lyalina | first3=R. | last3=Macdonald | first4=B. | last4=Bagiński | first5=Y. | last5=Savchenko | first6=P. | last6=Jokubauskas | journal=Minerals | year=2019 | volume=9 | issue=12 | page=732 | doi=10.3390/min9120732| bibcode=2019Mine....9..732Z | doi-access=free }} Quartzolite is an extremely rare type of rock.{{cite web | url=http://www.bgs.ac.uk/downloads/start.cfm?id=7 | title=BGS Rock Classification Scheme, Volume 1: Classification of igneous rocks | publisher=British Geological Survey | date=1999 | access-date=19 November 2016 | last1=Gillespie | first1=M.R. | last2=Styles | first2=M.T. | pages=10}} No extrusive rock equivalent of quartzolite is known.{{cite book | title=Handbook of Rocks, Minerals, and Gemstones | publisher=Houghton-Mifflin Company | author=Schumann, Walter | year=1993 | location=Boston | pages=198 | isbn=978-0-395-51138-1}}
Synonyms
The use of the synonym "silexite" is discouraged because it is the French word for chert, which is a sedimentary rock.{{cite book |title=Glossary of Geology |publisher=American Geological Institute |last1=Neuendorf |first1=K. K. E. |last2=Mehl, Jr. |first2=J. P. |last3=Jackson |first3=J. A. |year=2005 |location=Alexandria, Virginia |pages=530 |isbn=978-3642066214 |edition=5th}} Other less common synonyms are "igneous quartz" and "peracidite".{{cite book | title = Dictionary of Gems and Gemology | publisher=Springer | author=Manutchehr-Danai, M. | year=2009 | location=Berlin | pages=778| doi=10.1007/978-3-540-72816-0_19824 | isbn=978-3-540-72795-8 | chapter=Silexite | edition=3rd }}
Examples
- Chrastava, Czech Republic
- Crag Mountain, Northfield, Massachusetts, United States{{Rp|118}}
- Jabal Hamra, Saudi Arabia{{cite journal | first1=Norman J. | last1= Jackson | first2=Colin J. | last2=Douch | title=Jabal Hamra REE-mineralized silexite, Hijaz region, Kingdom of Saudi Arabia | journal=Journal of African Earth Sciences | year=1986 | volume=4 | pages=269–274 | doi=10.1016/S0899-5362(86)80088-4| bibcode= 1986JAfES...4..269J }}
- Keivy, Kola Peninsula, Russia
- Lyon Mountain quadrangle, New York state, United States{{cite journal | title=Pegmatite, Silexite, and Aplite of Northern New York | author=Miller, William J. | journal=The Journal of Geology | year=1919 | volume=27 | issue=1 | pages=28–54 | doi=10.1086/622638| bibcode=1919JG.....27...28M | doi-access=free }}
- Moulting Pond, Newfoundland, Canada
- Qiabukanzhuota, China{{cite journal | title=Chronology and origin of Au-Cu deposits related to paleozoic intracontinental rifting in West Tianshan Mountains, NW China | last1=Li | first1=Huaqin | last2=Chen | first2=Fuwen | journal=Science in China Series B: Chemistry | year=2002 | volume=45 | pages=108–120 | doi=10.1007/BF02932212}}
- Saveh County, Iran{{cite journal | url=http://www.iotpe.com/IJTPE/IJTPE-2014/IJTPE-Issue20-Vol6-No3-Sep2014/2-IJTPE-Issue20-Vol6-No3-Sep2014-pp6-11.pdf | title=Petrology and Petrogenesis of Intrusive in North-East Saveh, Iran | first1=A . R. | last1=Shokouhian Rad | first2=Hadi | last2=Kazemi Koohbanani | first3=S. | last3=Kazemi Koohbanani | first4=N. | last4=Kazemi Koohbanani | journal=International Journal on Technical and Physical Problems of Engineering | year=2014 | volume=6 | pages=6–11 | issn=2077-3528}}
- Smaaland Cove, South Georgia{{cite journal | title=The Geology of South Georgia: VI. Larsen Harbour Formation | last=Mair | first=B.F. | journal=British Antarctic Survey Scientific Reports | date=1987 | volume=111 | pages=1–60}}{{Rp|19}}
- South Mountains, Arizona, United States{{Citation | last1=Greenberg | first1=R.M. | last2=Miranda | first2=E. | title=Strain localization in granodiorite mylonites: a microstructural and electron backscatter diffraction (EBSD) study of the South Mountains core complex, Arizona | year=2009 | journal=AGU Fall Meeting Abstracts| volume=2009 | pages=T33A–1859 | bibcode=2009AGUFM.T33A1859G}}
- Torrington, New South Wales, Australia{{cite web | title=Topaz | url=http://www.resourcesandenergy.nsw.gov.au/__data/assets/pdf_file/0019/238213/Topaz.pdf | publisher=NSW Department of Primary Industries | work=Industrial Mineral Opportunities | access-date=23 November 2016}}
Formation
Some occurrences of quartzolite are unlikely to have an entirely igneous origin; for example, two types of quartzolite that are associated with deposits of topaz in and around the Mole Granite pluton in Torrington, NSW, are believed to have formed in different ways. One type forms dykes and sills in the granite and in the surrounding metamorphic rocks. The other type has remnants of an earlier granite texture and is found on the outer edges of part of the pluton.{{cite web | url=http://www.toptung.com.au/Portals/Toptung/Torrington%20AUSIMM%20Presentation%20Mod.pdf | title=The Torrington Project | publisher=Top Tung | date=2015 | access-date=23 November 2016 | author=Skinner, Mike | archive-date=24 November 2016 | archive-url=https://web.archive.org/web/20161124024726/http://www.toptung.com.au/Portals/Toptung/Torrington%20AUSIMM%20Presentation%20Mod.pdf | url-status=dead }}