Lanthanite Explained

Lanthanite should not be confused with lanthanide.

Lanthanite-(La), Lanthanite-(Nd), Lanthanite-(Ce)
Category:	Carbonate minerals
Formula:	(REE)2(CO3)3·8(H2O)
Imasymbol:	Ltn^[1]
Strunz:	5.CC.25
Dana:	(La): 15.04.02.01 (Nd): 15.04.02.02 (Ce): 15.04.02.03
System:	Orthorhombic
Class:	Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m)
Symmetry:	Pbnb
Unit Cell:	a = 9.476(4)-9.483(6) b = 16.940(8)-16.938(11) c = 8.942(4)-8.965(3) [Å], Z = 4
Color:	Pale pink to purple
Habit:	Platy
Twinning:	Common on
Cleavage:	Micaceous, perfect on
Fracture:	Uneven
Tenacity:	Sectile
Mohs:	2.5
Luster:	Vitreous to pearly
Streak:	White
Density:	2.78-2.84 (measured), 2.79-2.816 (calculated)
Opticalprop:	Biaxial (-)
2V:	58-61° (measured), 60-63.5° (calculated)
References:	^[2]

Lanthanites are a group of isostructural rare earth element (REE) carbonate minerals. This group comprises the minerals lanthanite-(La),^{[3] [4]} lanthanite-(Ce),^[5] and lanthanite-(Nd).^[6] This mineral group has the general chemical formula of (REE)₂(CO₃)₃·8(H₂O). Lanthanites include La, Ce, and Nd as major elements and often contain subordinate amounts of other REEs including praseodymium (Pr), samarium (Sm), europium (Eu) and dysprosium (Dy).^[7] The lanthanite crystal structure consists of layers of 10-fold coordinated REE-oxygen (O) polyhedra and carbonate (CO₃²⁻) groups connected by hydrogen bonds to interlayer water molecules, forming a highly hydrated structure.^[8]

Origin and formation

Lanthanites are frequently found as secondary minerals formed by the weathering of other minerals and occur as scales or tabular crystals. Originally identified at Bastnäs, Sweden,^[9] they have subsequently been found in New Zealand,^[10] Japan,^[11] Madagascar,^[12] Wales,^[13] China,^[14] France,^[15] Germany,^[16] Greenland,^[17] Finland,^[18] Canada,^[19] Austria,^[20] Romania,^[21] Norway,^[22] Brazil,^[23] and the United States.^[24]

Recently, a different mechanism of formation of lanthanites was discovered: Lanthanites also can form via a highly hydrated, nanoparticulate and poorly ordered carbonate precursor.^[25] The lifetime of this rare-earth bearing precursor as well as the kinetics of crystallization of the various REE-lanthanites are dependent on the specific trivalent rare-earth ion involved in the reaction. The times needed for lanthanites to fully crystallize increase linearly with the ionic potential of the trivalent rare-earth ion (La³⁺, Ce³⁺, Pr³⁺, Nd³⁺) present in their structure. The differences in these ion sizes and ionic potential as well as differences in dehydration energy of the trivalent rare-earth ions control the lifetime of the poorly ordered precursor and thus also the crystallization kinetics of the lanthanites. Furthermore, they also affect the structural characteristics (e.g. unit-cell dimensions and standard shape) of the crystals.

Other sources

• Webmineral data
• Mindat with location data
• RRUFF Project

Further reading

• Miyawaki R, Matsubara S, Yokoyama K, Iwano S, Hamasaki K, Yukinori I (2003) Kozoite-(La), La(CO3)(OH), a new mineral from Mitsukoshi, Hizen-cho, Saga Prefecture, Japan. Journal of Mineralogical and Petrological Sciences 98, 137–141.
• Miyawaki, R., Matsubara, S., Yokoyama, K., Takeuchi, K., Terada, Y., & Nakai, I. (2000). Kozoite-(Nd), Nd (CO3)(OH), a new mineral in an alkali olivine basalt from Hizen-cho, Saga Prefecture, Japan. American Mineralogist, 85(7-8), 1076–1081.
• SHEARD, E.R., WILLIAMS-JONES, A.E., HEILIGMANN, M., PEDERSON, C. AND TRUEMAN, D.L. (2012) Controls on the concentration of zirconium, niobium, and the rare earth elements in the Thor Lake rare metal deposit, Northwest Territories, Canada. Economic Geology, 107(1), 81-104.
• Nordrum, F. S. (2007): Nyfunn av mineraler i Norge 2006–2007. STEIN 34 (2), 14–26.
• Husdal, T. (2009): Ancylittmineraler i Norge. Norsk Bergverksmuseum Skrift 41, 33 - 42.
• Larsen, A. O. (1994): Drusemineraler fra Solumsåsen pukkverk, Holmestrand. STEIN 21 (2), 136–141.
• Minerals of Georgia: Their properties and occurrences. Robert Cook GGWRD Bull 92.
• American Mineralogist: 38: 1169-1183*New Data on Minerals (2004): 39: 50–64.
• Jensen (1978) Minerals of New York State.*Dana 6: 767; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837–1892, Volume II: 242.*Rocks & Minerals: 6: 26; Rocks & Minerals: 10: 33–36, 58.
• Handbook of Mineralogy - Anthony, Bideaux, Bladh, Nichols; Hess, F. L. 1908. Minerals of the rare-earth metals at Baringer Hill, Llano County, Texas. U.S. Geological Survey Bulletin 340. 286–294.
• Schooner, Richard. (1958): The Mineralogy of the Portland-East Hampton-Middletown-Haddam Area in Connecticut (With a few notes on Glastonbury and Marlborough).

Notes and References

1. 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.
2. http://www.mindat.org/min-46.html Lanthanite on Mindat
3. Haidinger W (1845) Zweite Klasse: Geogenide. II. Ordnung. Baryte. III. Cerebaryt. Lanthanit., in Handbuch der Bestimmenden Mineralogie, Bei Braumüller and Seidel (Wien) 499-506.
4. Nickel E H, Mandarino J A (1987) Procedures involving the IMA Commission on New Minerals and Mineral Names and guidelines on mineral nomenclature, American Mineralogist 72, 1031-1042.
5. Bevins R E, Rowbotham G, Stephens F S, Turgoose S, Williams P A (1985) Lanthanite-(Ce), (Ce,La,Nd)2(CO3)3·8H2O, a new mineral from Wales, U.K.. American Mineralogist 70, 411-413.
6. Roberts A C, Chao G Y, Cesbron F (1980) Lanthanite-(Nd), a new mineral from Curitiba, Parana, Brazil, Geological Survey of Canada Paper 80-1C, 141-142.
7. The Canadian Mineralogist 45 (2007) 1389-1396.
8. Morrison, S. M., Andrade, M. B., Wenz, M. D., Domanik, K. J., & Downs, R. T. (2013). Lanthanite-(Nd), Nd2 (CO3) 3.8 H2O. Acta Crystallographica Section E: Structure Reports Online, 69(3), i15-i16.
9. Berzelius, J. (1825). Taschenbuch für die gesamte Mineralogie mit Hinsicht auf die neuesten Entdeckungen, 19, 193-218.
10. Graham, I.T., Pogson, R.E.,Colchester, D.M., Hergt, J. Martin, R. & Williams, P.A. (2007): Pink Lanthanite-(Nd) from Whitianga Quarry, Coromandel Peninsula, New Zealand. Canadian Mineralogist. 45: 1389-1396
11. American Mineralogist: 71(7-8): 1028-1033.
12. Behier, J. (1960): Contribution á la mineralogie de Madagascar. Annales Géologiques de Madagascar XXIX, Tananarive, p 18
13. Amer.Min.(1985) 70, 411-413
14. Zhang Peishan, Yang Zhuming, Tao Kejie, and Yang Xueming (1996): "Mineralogy and Geology of Rare Earths in China", Science Press (Beijing), 226 pp.
15. Remy, P., Gatel, P., Meisser, N. (2014): Indice à terres rares de Mosset (Pyrénées-Orientales). Le Cahier des Micromonteurs, 1-2014, 3-17.
16. Gröbner, J., Hajek, W., Junker, R. & Nikoleizig, J. (2011): Neue Mineralschätze des Harzes. Papierflieger Verlag GmbH, Clausthal-Zellerfeld, Germany, 127 pp.
17. Petersen, O. V. and Secher, K. (1993): The minerals of Greenland, The Mineralogical Record, Vol. 24(2), 1-65
18. Sotka, P. 1984. Juuka, Panjavaara: Ce-La-Sr-mineraalien esiintyminen karbonaattijuonissa. Outokumpu OY raportti 070/4312 08A/PMS/1984.
19. HORVÁTH, L. & PFENNINGER-HORVÁTH, E. (2000) I minerali di Mont-Saint-Hilaire (Québec, Canada) Rivista Mineralogica Italiana, XXIV, 140-202.
20. G. Niedermayr, I. Praetzel: Mineralien Kärntens, 1995.
21. Szakáll, S. & Kristály, F., Eds. (2010): Mineralogy of Székelyland, Eastern Transylvania, Romania. Csík County Nature and Conservation Society, Miercurea-Ciuc, Romania, 321 pp.
22. Sæbø, P.Chr. (1961): Contribution to the mineralogy of Norway. No.11. On lanthanite in Norway. Norsk Geologisk Tidsskrift. 41: 311-317
23. Roberts, A.C., G.Y. Chao, and F. Cesbron (1980) Lanthanite-(Nd), a new mineral from Curitiba, Paran ́a, Brazil. Geol. Surv. Canada, Paper 80-1C, 141–142.
24. "Minerals of Colorado, updated & revised", p. 14, by Eckel, Edwin B., 1997.
25. Rodriguez-Blanco, J.D., Vallina, B., Blanco, J.A. and Benning, L.G. (2014) The role of REE³⁺ in the crystallization of lanthanites. Mineralogical Magazine, 78, 1373–1380. DOI: 10.1180/minmag.2014.078.6.03