Tobermorite

{{short description|Inosilicate alteration mineral in metamorphosed limestone and in skarn}} {{distinguish|Torbernite|Torbanite}} {{use dmy dates|date=August 2025}} {{Infobox mineral | name = Tobermorite | category = Silicate mineral, Calcium silicate hydrate | image = Tobermorite-t08-76a.jpg | caption = Crystalline mass of tobermorite | formula = Ca5Si6O16(OH)2·4H2O, or; Ca5Si6(O,OH)18·5H2O | IMAsymbol = Tbm<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 = 702.36 g/mol | strunz = 9.DG.10 | system = Orthorhombic | class = Disphenoidal (222) H-M symbol: (2 2 2) | symmetry = ''C2221'' (no. 20) | unit cell = a = 11.17 Å, b = 7.38 Å c = 22.94 Å; β = 90°; Z = 4 | color = Pale pinkish white, white, brown | habit = As minute laths; fibrous bundles, rosettes or sheaves, radiating or plumose, fine granular, massive. | twinning = | cleavage = {001} Perfect, {100} Imperfect | fracture = | tenacity = | mohs = 2.5 | luster = Vitreous, silky in fibrous aggregates | polish = | refractive = nα = 1.570 nβ = 1.571 nγ = 1.575 | opticalprop = Biaxial (+) | birefringence = δ = 0.005 | dispersion = | pleochroism = | fluorescence= Fluorescent, Short UV:weak white to yellow, Long UV:weak white to yellow | absorption = | streak = White | gravity = 2.423 – 2.458 | diaphaneity = Translucent to translucent | other = | references = <ref name=Handbook>{{cite web |last1=Anthony |first1=John W. |last2=Bideaux |first2=Richard A. |last3=Bladh |first3=Kenneth W. |last4=Nichols |first4=Monte C. |title=Tobermorite |url=http://www.handbookofmineralogy.org/pdfs/tobermorite.pdf |website=Handbook of Mineralogy |publisher=Mineral Data Publishing |access-date=27 July 2022 |date=2005}}</ref><ref name=Mindat>{{mindat|id=3985|access-date=27 July 2022}}</ref><ref name=Webmin>{{Cite web|last1=Barthelmy|first1=David|year=2014|url=http://www.webmineral.com/data/Tobermorite.shtml|access-date=27 July 2022|title = Lavendulan Mineral Data|website=Webmineral.com}}</ref> }}

'''Tobermorite''' is a calcium silicate hydrate mineral with chemical formula: Ca5Si6O16(OH)2·4H2O or Ca5Si6(O,OH)18·5H2O.

Two structural varieties are distinguished: tobermorite-11 Å and tobermorite-14 Å. Tobermorite occurs in hydrated cement paste and can be found in nature as an alteration mineral in metamorphosed limestone and in skarn. It has been reported to occur in the Maqarin Area of north Jordan and in the Crestmore Quarry near Crestmore Heights, Riverside County, California.

Tobermorite was first described in 1880 for an occurrence in Scotland, on the Isle of Mull, around the locality of Tobermory.<ref name=Mindat/><ref>Scottish physician and amateur mineralogist Matthew Forster Heddle (1828–1897) first described tobermorite in: {{cite journal |last1=Heddle |title=Preliminary notice of substances which may prove to be new minerals. Part second. |journal=Mineralogical Magazine and Journal of the Mineralogical Society |date=1880 |volume=4 |pages=117–123 |doi=10.1180/minmag.1880.004.18.04 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015065876461&view=1up&seq=181&skin=2021|url-access=subscription }} See pp. 119–121.</ref>

==Use in Roman concrete== Aluminum-substituted tobermorite is understood to be a key ingredient responsible for the longevity of ancient undersea Roman concrete. The volcanic ash that Romans used for construction of sea walls contained phillipsite, and an interaction with sea water caused the crystalline structures in the concrete to expand and strengthen, making that material substantially more durable than modern concrete when exposed to sea water.<ref name="WashPost2017">[https://www.washingtonpost.com/news/speaking-of-science/wp/2017/07/04/ancient-romans-made-worlds-most-durable-concrete-we-might-use-it-to-stop-rising-seas/?tid=hybrid_collaborative_2_na Ancient Romans made world’s ‘most durable’ concrete. We might use it to stop rising seas], ''Washington Post'', Ben Guarino, July 4, 2017. Retrieved July 5, 2017.</ref><ref>[http://ceramics.org/ceramictechtoday/2013/06/07/ancient-lessons-roman-concrete-durable-green/ ''Ancient lessons: Roman concrete durable, green'', Jim Destefani, ed., Ceramic Tech Today, The American Ceramic Society, June 7, 2013]</ref><ref name="JacksonMulcahy2017">{{cite journal|last1=Jackson|first1=Marie D.|last2=Mulcahy|first2=Sean R.|last3=Chen|first3=Heng|last4=Li|first4=Yao|last5=Li|first5=Qinfei|last6=Cappelletti|first6=Piergiulio|last7=Wenk|first7=Hans-Rudolf|title=Phillipsite and Al-tobermorite mineral cements produced through low-temperature water-rock reactions in Roman marine concrete|journal=American Mineralogist|volume=102|issue=7|year=2017|pages=1435–1450|issn=0003-004X|doi=10.2138/am-2017-5993CCBY|url=https://cedar.wwu.edu/geology_facpubs/67|bibcode=2017AmMin.102.1435J|doi-access=free}}</ref> thumb|Crystal structure of tobermorite: elementary unit cell.

==Cement chemistry== {{unsourced|section|date=August 2018}} Tobermorite is often used in thermodynamical calculations to represent the pole of the most evolved calcium silicate hydrate (C-S-H). According to its chemical formula, its atomic Ca/Si or molar CaO/SiO2 (C/S) ratio is 5/6 (0.83). Jennite represents the less evolved pole with a C/S ratio of 1.50 (9/6).

==See also== * Other calcium silicate hydrate (C-S-H) minerals: ** {{annotated link|Afwillite}} ** {{annotated link|Gyrolite}} ** {{annotated link|Jaffeite}} ** {{annotated link|Jennite}} ** {{annotated link|Okenite}} ** {{annotated link|Thaumasite}} ** {{annotated link|Xonotlite}} * Other calcium aluminium silicate hydrate, (C-A-S-H) minerals: ** Hydrogarnet ** Hydrogrossular ** Hydrotalcite ** Katoite ** Tacharanite ({{chem2|Ca12Al2Si18O33(OH)36}})

==References== {{Reflist}}

==Further reading== {{Refbegin}} * American Mineralogist (1954) 39, 1038. * {{cite journal | last1 = Taylor | first1 = H. F. W. | title = The transformation of tobermorite into xonotlite | journal = Mineralogical Magazine and Journal of the Mineralogical Society | date = June 1959 | volume = 32 | issue = 245 | pages = 110–116 | issn = 0369-0148 | eissn = 2515-821X | doi = 10.1180/minmag.1959.32.245.03 | pmid = | bibcode = 1959MinM...32..110T | url = }} * {{Citation | last1 = Abdul-Jaber | first1 = Q.H. | last2 = Khoury | first2 = H. | year = 1998 | title = Unusual mineralisation in the Maqarin Area (North Jordan) and the occurrence of some rare minerals in the marbles and the weathered rocks | periodical = Neues Jahrb. Geol. Paläontol. Abh. | volume = 208 | issue = 1–3 | pages = 603–629 | url = | doi = 10.1127/njgpa/208/1998/603 }} * {{Cite journal | last = Chen | first = Jeffrey J. |author2=Jeffrey J. Thomas |author3=Hal F.W. Taylor |author4=Hamlin M. Jennings | year = 2004 | title = Solubility and structure of calcium silicate hydrate | journal = Cement and Concrete Research | volume = 34 | issue = 9 | pages = 1499–1519 | doi = 10.1016/j.cemconres.2004.04.034 | issn = 0008-8846 | citeseerx = 10.1.1.568.4216 }} * {{Cite journal | last = Coleman | first = Nichola J. | year = 2011 | title = 11 Ä tobermorite ion exchanger from recycled container glass | journal = International Journal of Environment and Waste Management | volume = 8 | issue = 3–4 | pages = 366–382 | doi = 10.1504/IJEWM.2011.042642 }} * {{Cite journal | last = Currie | first = J. | year = 1905 | title = Note on some new localities for gyrolite and tobermorite | journal = Mineralogical Magazine | volume = 14 | issue = 64 | pages = 93–95 | doi=10.1180/minmag.1905.014.64.06 | bibcode = 1905MinM...14...93C }} * {{Cite journal | last = Eakle | first = Arthur S. | year = 1927 | title = Famous mineral localities: Crestmore, Riverside County, California | journal = American Mineralogist | volume = 12 | pages = 319–321 | url = http://www.minsocam.org/MSA/collectors_corner/arc/crestmoreca1.htm | accessdate = 2009-11-01 }} * {{Cite journal | last = Kikuma | first = J. |author2=Tsunashima M. |author3=Ishikawa T. |author4=Matsuno S. |author5=Ogawa A. |author6=Matsui K. |author7=Sato M. | year = 2009 | title = Hydrothermal formation of tobermorite studied by in situ X-ray diffraction under autoclave condition |journal = Journal of Synchrotron Radiation |volume = 16 | issue = 5 |pages = 683–686 | doi=10.1107/s0909049509022080 | pmid = 19713643 |doi-access = free }} * {{Cite journal | last = McConnell | first = J.D.C. | year = 1954 | title = The hydrated calcium silicates riversideite, tobermorite and plombierite | journal = Mineralogical Magazine | volume = 30 | issue = 224 | pages = 293–305 | doi = 10.1180/minmag.1954.030.224.02 | bibcode = 1954MinM...30..293M | s2cid = 94792892 }} * {{Cite journal | last = Merlino | first = S. | author2 = Bonaccorsi E. | author3 = Armbruster T. | title = Tobermorites: Their real structure and order-disorder (OD) character, Sample: 9 Angstrom | journal = American Mineralogist | volume = 84 | issue = 10 | year = 1999 | pages = 1613–1621 | url = http://rruff.geo.arizona.edu/AMS/minerals/Tobermorite | doi = 10.2138/am-1999-1015 | s2cid = 58927981 | url-access = subscription }} * {{Cite journal |last = Merlino |first = S. |author2 = Bonaccorsi E. |author3 = Armbruster T. |title = The real structure of tobermorite 11A: normal and anomalous forms, OD character and polytypic modifications (Note: MDO2 – synchrotron radiation source. Locality: Bascenov, Urals, Russia) |journal = European Journal of Mineralogy |volume = 13 |issue = 3 |year = 2001 |pages = 577–590 |url = http://rruff.geo.arizona.edu/AMS/minerals/Tobermorite |doi = 10.1127/0935-1221/2001/0013-0577 |bibcode = 2001EJMin..13..577M |url-access= subscription }} * {{Cite journal | last = Naomichi | first = Hara | year = 2000 | title = Formation of jennite and tobermorite from amorphous silica. | journal = J. Soc. Inorg. Mater. Japan | volume = 7 | issue = 285 | pages = 133–142 | issn = 1345-3769 | url = http://sciencelinks.jp/j-east/article/200011/000020001100A0298196.php | accessdate = 2009-02-04 | archive-date = 2012-02-17 | archive-url = https://web.archive.org/web/20120217004545/http://sciencelinks.jp/j-east/article/200011/000020001100A0298196.php | url-status = dead }} {{Refend}}

==External links== * [http://rruff.geo.arizona.edu/AMS/result.php?mineral=Tobermorite Tobermorite in the American Mineralogist Crystal Structure Database] {{commonscat|Tobermorite}}

Category:Calcium compounds Category:Calcium minerals Category:Cement Category:Crestmore Heights, California Category:Geology of Riverside County, California 4.5 Category:Inorganic compounds Category:Inosilicates Category:Minerals in space group 20 Category:Orthorhombic minerals