Tobermorite Explained
Tobermorite should not be confused with Torbernite.
| Tobermorite |
| Category: | Silicate mineral,
Calcium silicate hydrate |
| Formula: | Ca5Si6O16(OH)2·4H2O, or;
Ca5Si6(O,OH)18·5H2O |
| Imasymbol: | Tbm[1] |
| 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. |
| Cleavage: | Perfect, Imperfect |
| Mohs: | 2.5 |
| Luster: | Vitreous, silky in fibrous aggregates |
| Refractive: | nα = 1.570 nβ = 1.571 nγ = 1.575 |
| Opticalprop: | Biaxial (+) |
| Birefringence: | δ = 0.005 |
| Fluorescence: | Fluorescent, Short UV:weak white to yellow, Long UV:weak white to yellow |
| Streak: | White |
| Gravity: | 2.423 – 2.458 |
| Diaphaneity: | Translucent to translucent |
| References: | [2] [3] |
Tobermorite is a calcium silicate hydrate mineral with chemical formula:Ca5Si6O16(OH)2·4H2O orCa5Si6(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.[4]
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.[5] [6] [7]
Cement chemistry
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
Further reading
- American Mineralogist (1954) 39, 1038.
- Taylor . H. F. W. . The transformation of tobermorite into xonotlite . Mineralogical Magazine and Journal of the Mineralogical Society . June 1959 . 32 . 245 . 110–116 . 0369-0148 . 2515-821X . 10.1180/minmag.1959.32.245.03 . 1959MinM...32..110T .
- Chen. Jeffrey J.. Jeffrey J. Thomas . Hal F.W. Taylor . Hamlin M. Jennings . 2004. Solubility and structure of calcium silicate hydrate. Cement and Concrete Research. 34. 9. 1499–1519. 10.1016/j.cemconres.2004.04.034. 0008-8846. 10.1.1.568.4216.
- Coleman. Nichola J.. 2011. 11 Ä tobermorite ion exchanger from recycled container glass. International Journal of Environment and Waste Management. 8. 3–4. 366–382. 10.1504/IJEWM.2011.042642.
- Currie. J.. 1905. Note on some new localities for gyrolite and tobermorite. Mineralogical Magazine. 14. 64. 93–95. 10.1180/minmag.1905.014.64.06. 1905MinM...14...93C.
- Eakle. Arthur S.. 1927. Famous mineral localities: Crestmore, Riverside County, California. American Mineralogist. 12. 319–321. 2009-11-01.
- Kikuma. J.. Tsunashima M. . Ishikawa T. . Matsuno S. . Ogawa A. . Matsui K. . Sato M. . 2009. Hydrothermal formation of tobermorite studied by in situ X-ray diffraction under autoclave condition. Journal of Synchrotron Radiation. 16. 5. 683–686. 10.1107/s0909049509022080. 19713643. free.
- McConnell. J.D.C.. 1954. The hydrated calcium silicates riversideite, tobermorite and plombierite. Mineralogical Magazine. 30. 224. 293–305. 10.1180/minmag.1954.030.224.02. 1954MinM...30..293M. 94792892.
- Merlino . S. . Bonaccorsi E. . Armbruster T. . Tobermorites: Their real structure and order-disorder (OD) character, Sample: 9 Angstrom . American Mineralogist . 84 . 10 . 1999 . 1613–1621 . 10.2138/am-1999-1015 . 58927981 .
- Merlino . S. . Bonaccorsi E. . Armbruster T. . The real structure of tobermorite 11A: normal and anomalous forms, OD character and polytypic modifications (Note: MDO2 – synchrotron radiation source. Locality: Bascenov, Urals, Russia) . European Journal of Mineralogy . 13 . 3 . 2001 . 577–590 . 10.1127/0935-1221/2001/0013-0577 . 2001EJMin..13..577M.
- Naomichi. Hara. 2000. Formation of jennite and tobermorite from amorphous silica.. J. Soc. Inorg. Mater. Japan. 7. 285. 133–142. 1345-3769. 2009-02-04. 2012-02-17. https://web.archive.org/web/20120217004545/http://sciencelinks.jp/j-east/article/200011/000020001100A0298196.php. dead.
External links
Notes and References
- Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
- Web site: Anthony . John W. . Bideaux . Richard A. . Bladh . Kenneth W. . Nichols . Monte C. . Tobermorite . Handbook of Mineralogy . Mineral Data Publishing . 27 July 2022 . 2005.
- Web site: Barthelmy. David. 2014. Lavendulan Mineral Data. 27 July 2022. Webmineral.com.
- Scottish physician and amateur mineralogist Matthew Forster Heddle (1828–1897) first described tobermorite in: Heddle . Preliminary notice of substances which may prove to be new minerals. Part second. . Mineralogical Magazine and Journal of the Mineralogical Society . 1880 . 4 . 117–123 . 10.1180/minmag.1880.004.18.04 . See pp. 119–121.
- 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
- 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
- Jackson. Marie D.. Mulcahy. Sean R.. Chen. Heng. Li. Yao. Li. Qinfei. Cappelletti. Piergiulio. Wenk. Hans-Rudolf. Phillipsite and Al-tobermorite mineral cements produced through low-temperature water-rock reactions in Roman marine concrete. American Mineralogist. 102. 7. 2017. 1435–1450. 0003-004X. 10.2138/am-2017-5993CCBY. 2017AmMin.102.1435J. free.
