Editing Topaz (section)

{{short description|Silicate mineral}}
{{About|the mineral or gemstone}}
{{Use American English|date=May 2021}}
{{Infobox mineral
| name       = Topaz
| category   = [[silicate mineral|Nesosilicate]]
| boxwidth   =
| boxbgcolor = #8F573F
| boxtextcolor = #FFFFFF
| image      = Topaze, quartz fumé 1.jpg
| imagesize  = 270px
| caption    = Topaz crystal on white matrix
| formula    = {{chem2|Al2SiO4(F, OH)2}}
| IMAsymbol   = Tpz<ref>{{cite magazine |last=Warr|first=L. N. |date=2021 |title=IMA–CNMNC approved mineral symbols |magazine=[[Mineralogical Magazine]] |volume=85 |issue=3 |pages=291–320 |doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}</ref>
| strunz     = 9.AF.35
| system     = [[orthorhombic crystal system|Orthorhombic]]
| class      = [[bipyramid|Dipyramidal]] (mmm)<br>[[H–M symbol]]: (2/m 2/m 2/m)
| symmetry   = ''Pbnm''
| unit cell  = a&nbsp;=&nbsp;4.65&nbsp;[[Ångström|Å]], b&nbsp;=&nbsp;8.8&nbsp;Å,<br>c&nbsp;=&nbsp;8.4&nbsp;Å; Z&nbsp;=&nbsp;4
| color      = Colorless (if impurities are absent), white, blue, brown, orange, gray, yellow, yellowish brown, green, pink, reddish pink, or even red
| habit      = Prismatic crystal
| twinning   = Rarely on [111]<ref>{{cite book |last1=Nesse |first1=William D. |title=Introduction to mineralogy |date=2000 |publisher=[[Oxford University Press]] |location=New York |isbn=9780195106916 |page=313}}</ref>
| cleavage   = [001] Perfect
| fracture   = [[conchoidal fracture|Subconchoidal]] to uneven
| mohs       = 8 (defining mineral)
| luster      = Vitreous
| refractive  = n{{sub|α}} = 1.606–1.629<br />n{{sub|β}} = 1.609–1.631<br />n{{sub|γ}} = 1.616–1.638
| opticalprop = Biaxial (+)
| birefringence = δ = 0.010
| pleochroism = Weak in thick sections X = yellow; Y = yellow, violet, reddish; Z = violet, bluish, yellow, pink
| fluorescence= Golden yellow under short UV; [[cream (colour)|cream]] under long UV
| streak      = White
| gravity     = 3.49–3.57
| diaphaneity = Transparent
| other       =
| references  = <ref>{{cite book |last1=Hurlbut|first1=Cornelius S. |last2=Klein|first2=Cornelis |year=1985 |title=Manual of Mineralogy |publisher=[[Wiley (publisher)|Wiley]] |edition=20 |isbn=0-471-80580-7}}</ref><ref name="Handbook">{{cite book |editor1=Anthony, John W. |editor2=Bideaux, Richard A. |editor3=Bladh, Kenneth W. |editor4=Nichols, Monte C. |title=Handbook of Mineralogy |publisher=Mineralogical Society of America |place=Chantilly, VA, US |chapter-url=http://rruff.geo.arizona.edu/doclib/hom/topaz.pdf |chapter=Topaz |access-date=December 5, 2011 |volume=II (Silica, Silicates) |year=1995 |isbn=978-0-9622097-1-0}}</ref><ref name="Mindat">[http://www.mindat.org/show.php?id=3996&ld=1&pho= Topaz]. Mindat.org. Retrieved on 2011-10-29.</ref><ref name=Webmineral>[http://webmineral.com/data/Topaz.shtml Topaz]. Webmineral.com. Retrieved on 2011-10-29.</ref>
}}

'''Topaz''' is a [[silicate mineral]] made of [[aluminium|aluminum]] and [[fluorine]] with the [[chemical formula]] [[aluminium|Al]]{{sub|2}}[[silicon|Si]][[oxygen|O]]{{sub|4}}([[fluorine|F]], [[hydroxide|OH]]){{sub|2}}. It is used as a [[gemstone]] in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden-brown to yellow-orange.<ref name=":0">{{Cite journal |last=Menzies |first=Michael A. |date=2023-12-08 |title=Connoisseur's Choice: Topaz from Granite Pegmatites: Limoeiro Mine, Virgem da Lapa, Araçuaí Pegmatite District, Minas Gerais, Brazil |url=http://dx.doi.org/10.1080/00357529.2023.2253100 |journal=Rocks & Minerals |volume=99 |issue=1 |pages=36–55 |doi=10.1080/00357529.2023.2253100 |s2cid=266145193 |issn=0035-7529|url-access=subscription }}</ref> Topaz is often treated with heat or radiation to make it a deep blue, reddish-orange, pale green, pink, or purple.<ref>{{Cite web|title=Topaz Value, Price, and Jewelry Information|url=https://www.gemsociety.org/article/topaz-jewelry-and-gemstone-information/|access-date=2021-11-16|website=International Gem Society|language=en}}</ref>

Topaz is a [[nesosilicate]] [[mineral]], and more specifically, an aluminosilicate mineral.<ref>{{Cite journal |last1=Tennakoon |first1=Sumudu |last2=Peng |first2=Ye |last3=Mookherjee |first3=Mainak |last4=Speziale |first4=Sergio |last5=Manthilake |first5=Geeth |last6=Besara |first6=Tiglet |last7=Andreu |first7=Luis |last8=Rivera |first8=Fernando |date=2018-01-22 |title=Single crystal elasticity of natural topaz at high-temperatures |journal=Scientific Reports |language=en |volume=8 |issue=1 |page=1372 |doi=10.1038/s41598-017-17856-3 |issn=2045-2322 |pmc=5778148 |pmid=29358663|bibcode=2018NatSR...8.1372T }}</ref> It is one of the hardest naturally occurring minerals and has a relatively low [[index of refraction]]. It has the orthorhombic [[crystal system]] and a dipyramidial [[crystal class]].<ref>{{Cite book |title=Handbook of mineralogy. 2,2: Silica, Silicates: Pt. 2 |date=1995 |publisher=Mineral Data Publ |isbn=978-0-9622097-1-0 |location=Tucson, Ariz}}</ref>

It occurs in many places in the world. Some of the most popular places where topaz is sourced are Brazil and Russia.<ref name=":0" /> Topaz is often mined in open pit or alluvial settings.<ref name=":6">{{Cite web |title=Topaz Mining: Balancing Resource Extraction and Sustainability |url=https://www.brilliyond.com/blog/topaz-mining |access-date=2024-03-20 |website=www.brilliyond.com}}</ref>