Lizardite

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Lizardite
Lizardit.jpg
General
Category Minerals
Formula Mg3(Si2O5)(OH)4 [1]
IMA symbol Lz [2]
Strunz classification 9.ED.15
Dana classification 71.01.2b.02
Crystal system Trigonal
Identification
ColorGreen, red, purple, black, brown, light yellow to white
Mohs scale hardness2.5
Luster Resinous, waxy, greasy
Streak White
Specific gravity 2.55

Lizardite is a mineral from the serpentine subgroup [3] with formula Mg3(Si2O5)(OH)4, and the most common type of mineral in the subgroup. [4] It is also a member of the kaolinite-serpentine group. [5]

Contents

Lizardite may form a solid-solution series with the nickel-bearing népouite (pure end-member: Ni3(Si2O5)(OH)4). Intermediate compositions (Mg,Ni)3(Si2O5)(OH)4 are possible, with varying proportions of magnesium and nickel. [6] However, the lizardite end-member is much more common than pure népouite, a relatively rare mineral most often formed by the alteration of ultramafic rocks.

Extremely fine-grained, scaly lizardite (also called orthoantigorite) comprises much of the serpentine present in "serpentine marbles". It is triclinic, has one direction of perfect cleavage, and may be white, yellow or green. Lizardite can be translucent or opaque, and have a soapy feel. It may be pseudomorphous after enstatite, olivine or pyroxene, in which case the name bastite is sometimes applied. Bastite may have a silky lustre. [1]

Name

Lizardite was named by Eric James William Whittaker and Jack Zussman in 1955 after the place it was first reported, the Lizard Peninsula, (from the Cornish : An Lysardh) in southern Cornwall, England, United Kingdom.

Scyelite is a synonym of lizardite. [1]

Characteristics

Chemistry

Antigorite and lizardite commonly coexist metastably; [7] : 24  lizardite may also be able to turn into antigorite at over 350 degrees. [8] : 712 

Lizardite contains H2O in excess of the nominal formula, as does chrysotile. It has a high amount of Fe2O3 and a low amount of FeO. [9] : 8 

One study found that lizardite has a high amount of SiO2 and a low amount of Al2O3. [10] : 193 

Formation

Lizardite is commonly a result from the hydrothermal metamorphism or retrograde metamorphism of mafic minerals such as olivine, pyroxene or amphibole, in ultrabasic rocks. [11]

Occurrence

Geological occurrence

Lizardite is commonly found in ophiolite [12] and is often intergrown with brucite. [9] : 8  It is also found with magnetite [11] and the other serpentine minerals. [13] : 118–119 

Locations found

Canada

As of 1989, only a single specimen of lizardite had been found in Mont-Saint-Hilaire, Quebec where it may occur in altered pegmatites. [14] : 184 

United States

Lizardite can be found in the United States. [15] In Pennsylvania It was discovered in the 1960s. [16] : 55  With it being the most abundant mineral in Nottingham County Park. [17] In Minnesota it can be found on the north shore of Lake Superior. [1] In Montana, the Stillwater igneous complex is a prominent location for the mineral. [15]

United Kingdom

Lizardite has a type locality at Lizard Peninsula, Cornwall, in the United Kingdom. [1] It is found in green, red purple, brown and black form and used as both a semi-precious gemstone or for ornamental uses.

Scotland is a notable source of lizardite. [18] Lizardite has been reported in Wales. At Holy Island, Anglesey lizardite has been found to be associated with antigorite. [11]

South Africa

In the Frank Smith mine located in South Africa, lizardite was the dominant serpentine mineral. [10] : 212  Orange lizardite has been found at the Wessels mine. [19]

Other

It can also be found in Japan, Italy, and Australia. [20]

References

  1. 1 2 3 4 5 "Lizardite". Mindat.org .
  2. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  3. ↑ Allaby, Michael (2020-01-09). A Dictionary of Geology and Earth Sciences. Oxford University Press. ISBN   978-0-19-257570-8.
  4. ↑ "Lizardite gemstone information". www.gemdat.org. Retrieved 2021-10-26.
  5. ↑ Gaines, Richard V.; Skinner, H. Catherine W.; Foord, Eugene E.; Mason, Brian; Rosensweig, Abraham (1997). Dana's new mineralogy : the system of mineralogy of James Dwight Dana and Edward Salisbury Dana (8th, entirely rewritten and greatly enl. ed.). New York: Wiley. ISBN   978-0471193104.
  6. ↑ Brindley, G.W.; Wan, Hsien-Ming (1975). "Compositions, structures, and thermal behavior of nickel-containing minerals in the lizardite-nepouite series". American Mineralogist. 60: 863–871. Retrieved 3 November 2021.
  7. ↑ Alexander, Earl B.; Coleman, Robert G.; Keeler-Wolfe, Todd; Keeler-Wolfe, Senior Vegetation Ecologist Wildlife and Habitat Data Analysis Branch Todd; Harrison, Susan P. (2007-03-22). Serpentine Geoecology of Western North America: Geology, Soils, and Vegetation. Oxford University Press, USA. ISBN   978-0-19-516508-1.
  8. ↑ Earth and Life Processes Discovered from Subseafloor Environments: A Decade of Science Achieved by the Integrated Ocean Drilling Program (IODP). Elsevier. 2014-12-03. ISBN   978-0-444-62611-0.
  9. 1 2 Roberts, B. A.; Proctor, J. (2012-12-06). The Ecology of Areas with Serpentinized Rocks: A World View. Springer Science & Business Media. ISBN   978-94-011-3722-5.
  10. 1 2 Deer, William Alexander; Howie, Robert Andrew; Zussman, J. (2009). Rock Forming Minerals: Layered Silicates Excluding Micas and Clay Minerals, Volume 3B. Geological Society of London. ISBN   978-1-86239-259-5.
  11. 1 2 3 "Mineral Database - Mineralogy of Wales". National Museum Wales. Retrieved 2021-10-26.
  12. ↑ Laurora, Angela; Brigatti, Maria Franca; Maiferrari, Daniele; Galli, Ermanno; Rossi, Antonio; Ferrari, Massimo (2011). "The crystal chemistry of lizardite-1T from northern Apennines ophiolites near Modena, Italy" (PDF). The Canadian Mineralogist. 49 (4): 1045–1054. Bibcode:2011CaMin..49.1045L. doi:10.3749/canmin.49.4.1045 . Retrieved 3 November 2021.
  13. ↑ Pichler, Hans; Schmitt-Riegraf, Cornelia (2012-12-06). Rock-forming Minerals in Thin Section. Springer Science & Business Media. ISBN   978-94-009-1443-8.
  14. ↑ Mandarino, Joseph Anthony; Anderson, Violet (1989-03-31). Monteregian Treasures: The Minerals of Mont Saint-Hilaire, Quebec. CUP Archive. ISBN   978-0-521-32632-2.
  15. 1 2 "Lizardite". National Gem Lab. 2017-03-14. Retrieved 2021-10-27.
  16. ↑ Montgomery, Arthur (2008). Mineralogy of Pennsylvania 1922-1965: Supplementing and Updating Gordon's the Mineralogy of Pennsylvania (1922). Academy of Natural Sciences. ISBN   978-1-4223-1786-0.
  17. ↑ Pazzaglia, Frank James (2006-01-01). Excursions in Geology and History: Field Trips in the Middle Atlantic States. Geological Society of America. p. 19. ISBN   978-0-8137-0008-3.
  18. ↑ "Serpentine Value, Price, and Jewelry Information - Gem Society". International Gem Society. Retrieved 2021-10-27.
  19. ↑ Rossman, George; Laurs, Brendan M. (2014). "Orange Lizardite from South Africa". Journal of Gemmology. 34 (2): 98–99. ISSN   1355-4565.
  20. ↑ "Gemmology | Classification | Lizardite". www.nmnhs.com. Retrieved 2021-11-02.
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