{{Short description|Sorosilicate mineral}} {{Infobox mineral | name = Ruizite | category = Sorosilicate | boxwidth = | boxbgcolor = | image = Ruizite-Calcite-180789.jpg | imagesize = 260px | caption = Clusters of ruizite on calcite from South Africa | formula = Ca<sub>2</sub>Mn<sub>2</sub>Si<sub>4</sub>O<sub>11</sub>(OH)<sub>4</sub>·2H<sub>2</sub>O<ref name=handbook/> | IMAsymbol = Rz<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=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> | molweight = | strunz = 9.BJ.35 | dana = 57.2.2.1 | system = Monoclinic | class = Prismatic (2/m) <br/><small>(same H-M symbol)</small> | symmetry = ''P''2<sub>1</sub>/c | unit cell = a = 11.95 Å, b = 6.17 Å <br/>c = 9.03 Å, β = 91.37°; Z = 4 | color = Orange, red-brown | habit = | twinning = Common on {100} | cleavage = | fracture = | tenacity = | mohs = 5 | luster = | polish = | refractive = n<sub>α</sub> = 1.663<br>n<sub>β</sub> = 1.715<br>n<sub>γ</sub> = 1.734 | opticalprop = Biaxial (-) | birefringence = δ = 0.071 | 2V = 60° | dispersion = | pleochroism = | fluorescence= | absorption = | streak = Apricot | gravity = | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Translucent | other = | references =<ref name=mindat>{{cite web|title=Ruizite|url=http://www.mindat.org/min-3476.html|publisher=Mindat|access-date=December 2, 2012}}</ref> }} '''Ruizite''' is a sorosilicate mineral with formula Ca<sub>2</sub>Mn<sub>2</sub>Si<sub>4</sub>O<sub>11</sub>(OH)<sub>4</sub>·2H<sub>2</sub>O. It was discovered at the Christmas mine in Christmas, Arizona, and described in 1977. The mineral is named for discoverer Joe Ana Ruiz.
==Description and occurrence== thumb|left|Ruizite from Arizona Ruizite is translucent and orange to red-brown in color with an apricot yellow streak.<ref name=mindat/> The mineral occurs as euhedral prisms up to {{convert|1|mm|in|abbr=on}} or as radial clusters of acicular (needle-like) crystals.<ref name=handbook/>
Ruizite is common at the Christmas mine.{{sfn|Williams|Duggan|1977|p=429}} The mineral is known from Arizona, Pennsylvania, and Northern Cape Province, South Africa.<ref name=mindat/> Ruizite occurs in association with apophyllite, bornite, calcite, chalcopyrite, datolite, diopside, grossular, inesite, junitoite, kinoite, orientite, pectolite, quartz, smectite, sphalerite, vesuvianite, and wollastonite.<ref name=handbook>{{cite encyclopedia|url=http://www.handbookofmineralogy.org/pdfs/ruizite.pdf |title=Ruizite |encyclopedia=Handbook of Mineralogy |editor1-first=John W. |editor1-last=Anthony|editor2-first=Richard A. |editor2-last=Bideaux|editor3-first=Kenneth W. |editor3-last=Bladh|editor4-first= Monte C. |editor4-last=Nichols |publisher=Mineralogical Society of America|location=Chantilly, VA}}</ref> Ruizite is found in veinlets or fracture surfaces of limestone metamorphosed into a calc-silicate assemblage. The mineral formed by retrograde metamorphism during cooling of a calc–silicate skarn assemblage in an oxidizing environment.<ref name=handbook/>{{sfn|Williams|Duggan|1977|p=429}}
==Crystal structure and chemistry== Ruizite crystallizes in the monoclinic crystal system and twinning is common along the {100} plane between exactly two crystals.<ref name=handbook/> Ruizite's formula was originally identified as CaMn(SiO<sub>3</sub>)<sub>2</sub>(OH)<sub>2</sub>·2H<sub>2</sub>O in 1977.{{sfn|Williams|Duggan|1977|p=429}} In 1984, Frank C. Hawthorne revised the formula to Ca<sub>2</sub>Mn<sub>2</sub>Si<sub>4</sub>O<sub>11</sub>(OH)<sub>4</sub>·2H<sub>2</sub>O.<ref>{{cite journal|last=Dunn|first=Pete J.|title=New Mineral Names, New Data|journal=American Mineralogist|date=March–April 1985|volume=70|issue=3–4|url=http://www.minsocam.org/ammin/AM70/AM70_436.pdf|page=441}}</ref> Ruizite's structure consists of edge-sharing Mnφ<sub>6</sub> octahedra, connected at corners into sheets and together into a lattice by clusters of Si<sub>4</sub>O<sub>11</sub>(OH)<sub>2</sub>.{{sfn|Hawthorne|1984|p=135}}
Nitric acid, hydrochloric acid, and potassium hydroxide have little effect on ruizite at low temperatures but readily dissolve the mineral at elevated temperatures.{{sfn|Williams|Duggan|1977|p=431}}
==History== During the investigation of junitoite at the Christmas mine in Christmas, Arizona, Joe Ana Ruiz and Robert Jenkins discovered an unknown brown mineral. Mine geologist Dave Cook located better specimens, and it was determined to be a new mineral species. The mineral was named ''ruizite'' in honor of Joe Ruiz as discoverer. Ruizite's properties were analyzed using a sample provided by Joseph Urban, and it was described in the journal ''Mineralogical Magazine'' in December 1977.{{sfn|Williams|Duggan|1977|p=432}} The International Mineralogical Association approved the mineral as IMA 1977-077.<ref name=IMA2012>{{cite web|title=The New IMA List of Minerals – A Work in Progress – Update: November 2012|url=http://pubsites.uws.edu.au/ima-cnmnc/IMA_Master_List_(2012-11).pdf|work=Commission on New Minerals, Nomenclature and Classification|publisher=International Mineralogical Association|access-date=December 2, 2012|page=146}}</ref> Type specimens are housed in the University of Arizona, Harvard University, the National Museum of Natural History, and The Natural History Museum.<ref name=handbook/>
==See also== *Carlosruizite
==References== {{Reflist|30em}}
;Bibliography *{{cite journal|last=Hawthorne|first=F. C.|title=The crystal structure of ruizite, a sorosilicate with an [Si<sub>4</sub>Ø<sub>13</sub>] cluster|journal=Tschermaks mineralogische und petrographische Mitteilungen|year=1984|volume=33|issue=2|pages=135–146|doi=10.1007/BF01083069|bibcode=1984MinPe..33..135H}} *{{cite journal|last1=Williams|first1=Sidney A.|last2=Duggan|first2=M.|title=Ruizite, A New Silicate Mineral from Christmas, Arizona|journal=Mineralogical Magazine|date=December 1977|volume=41|issue=320|pages=429–432|doi=10.1180/minmag.1977.041.320.01|bibcode=1977MinM...41..429W|s2cid=129031647 |url=http://www.minersoc.org/pages/Archive-MM/Volume_41/41-320-429.pdf}}
==Further reading== *{{cite journal|last1=Moore|first1=Paul B.|last2=Shen|first2=Jinchuan|last3=Araki |first3=Takaharu|title=Crystal chemistry of the <sup>2</sup><sub>∞</sub>[M<sup>3+</sup><sub>2</sub>φ<sub>2</sub>(TO<sub>4</sub>)<sub>2</sub><nowiki>]</nowiki>sheet: structural principles and crystal structures of ruizite, macfallite and orientite|journal=American Mineralogist|date=January–February 1985|volume=70|issue=1–2|pages=171–181|url=http://www.minsocam.org/ammin/AM70/AM70_171.pdf}}
==External links== {{commonscat-inline|Ruizite|lcfirst=yes}} {{Manganese minerals}}
Category:Monoclinic minerals Category:Minerals in space group 14 Category:Calcium minerals Category:Manganese(III) minerals Category:Sorosilicates Category:Dihydrate minerals Category:Hydroxide minerals Category:Minerals described in 1977