Editing Topaz (section)

==Localities and occurrence==
[[File:Topaze gisements.jpg|thumb|upright=1.5|Main topaz producing countries]]
Topaz is commonly associated with [[silicic]] igneous rocks of the [[granite]] and [[rhyolite]] type. It typically crystallizes in granitic [[pegmatites]]<ref name=":0" /> or in vapor cavities in rhyolite lava flows including those at [[Topaz Mountain]] in western Utah and [[Chivinar]] in South America. It can be found with [[fluorite]] and [[cassiterite]] in various areas including the [[Ural Mountains|Ural]] and [[Ilmensky Mountains|Ilmensky]] mountains of Russia, Afghanistan, Sri Lanka, the Czech Republic, Germany, Norway, Pakistan, Italy, Sweden, Japan, Brazil, Mexico; [[Flinders Island]], Australia; Nigeria, Ukraine and the United States. Topaz was found around the time of the 1700s in a pegmatite formation within the central [[Ural Mountains|Urals Mountains]] in Russia.<ref name=":0" />
[[File:Topaz from Pakistan.jpg|thumb|Topaz varieties found in Pakistan.]]
Brazil is one of the largest producers of topaz,<ref>{{cite web |access-date=November 23, 2016 |url=https://www.ayanajewellery.com/blog/topaz |title=Topaz Guide |publisher=Ayana Jewellery |archive-date=November 24, 2016 |archive-url=https://web.archive.org/web/20161124030229/https://www.ayanajewellery.com/blog/topaz |url-status=dead }}</ref> some clear topaz crystals from Brazilian pegmatites can reach boulder size and weigh hundreds of pounds. The Topaz of [[Aurangzeb]], observed by [[Jean Baptiste Tavernier]] weighed {{convert|157.75|carat}}.<ref>[http://www.farlang.com/gemstones/bahadur_handbook_of_precious_stones/page_128 Famous and Notheworthy Topazes] Rao Bahadur, A Handbook of Precious Stones, Geological Survey of India</ref> The [[American Golden Topaz]], a more recent gem, weighed {{convert|22,892.5|carat}}. Large, vivid blue topaz specimens from the St. Anns mine in [[Zimbabwe]] were found in the late 1980s.<ref>{{cite web|title=Topaz (Blue)|url=https://www.capeminerals.co.za/topaz-blue|website=Cape Minerals|access-date=7 February 2017|archive-date=8 February 2017|archive-url=https://web.archive.org/web/20170208132822/https://www.capeminerals.co.za/topaz-blue|url-status=dead}}</ref> Colorless and light-blue varieties of topaz are found in [[Precambrian]] granite in [[Mason County, Texas]]<ref>[https://tshaonline.org/handbook/online/articles/gpm01 Handbook of Texas Online – Mineral Resources and Mining]. Tshaonline.org. Retrieved on 2011-10-29.</ref> within the [[Llano Uplift]]. There is no commercial mining of topaz in that area.<ref>[https://web.archive.org/web/20070117051633/http://www.masontxcoc.com/topaz.htm Mason, Texas Chamber of Commerce Web site]</ref> It is possible to synthesize topaz.<ref>{{Cite journal |last=Rosenberg |first=Philip E. |date=1972 |title=Compositional variations in synthetic topaz |url=http://www.minsocam.org/ammin/AM57/AM57_169.pdf |journal=American Mineralogist |volume=57 |pages=169–187}}</ref>