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Paratooite-(La)

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Paratooite-(La)
Paratooite-(La): Locality: Paratoo copper mine, Yunta, Olary Province, South Australia, Australia. Field of view 6 mm.
General
CategoryCarbonate mineral
Formula
(repeating unit)
(La,Sr,Ca)4CuCa(Na,Ca)2(CO3)8
IMA symbolPto-La[1]
Strunz classification5/B.0; 5.AD.20 (Nickel-Strunz)
Crystal systemOrthorhombic
Crystal classDipyramidal: mmm
Space groupPbam
Unit cella = 7.2250, b = 12.7626 c = 10.0559 [Å]
Identification
Colorpale turquoise-blue to pale blue
Crystal habitblades (sheaves) intergrown to form spray-like aggregates
Cleavage{100} (possible)
Mohs scale hardness4 (probably)
Lustervitreous or pearly
Streakpale blue
Specific gravity1.97-2.02 (measured)
Optical propertiesbiaxial negative, α = 1.605(3), β = 1.696(3), γ = 1.752(2)
Pleochroismmoderate, very pale blue (X) to greenish blue (Y = Z)
2V angle72.6 °
References[2][3][4]

Paratooite-(La) is a complex lanthanum copper(II) calcium sodium carbonate mineral, representing a unique elemental combination among the known minerals. It is a secondary, weathering mineral.[5][6][7] There is a heterovalent diadochy substitution of lanthanum by strontium and calcium; also sodium is substituted by calcium in the mineral. Its structure proved to be more difficult to describe within the initial approach. It was later shown to be a superstructure of another rare earth carbonate mineral, carbocernaite.[8] The "-(La)" suffix in the mineral's name is known as Levinson suffix. It refers to the particular element, of a group of elements (notably lanthanides), that dominates in the particular structural site. As such, the element would show major, dominant occupancy at this particular site.[9]

References

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  1. ^ 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.
  2. ^ Pring, A., Wallwork, K., Brugger, J., Kolitsch, U. (2006) Paratooite-(La), a new lanthanum-dominant rare-earth copper carbonate from Paratoo, South Australia. Mineralogical Magazine, 70, 131-138
  3. ^ Mindat, Paratooite-(La), https://www.mindat.org/min-27579.html
  4. ^ Handbook of Mineralogy, Paratooite-(La), http://www.handbookofmineralogy.org/pdfs/paratooite-(La).pdf
  5. ^ Pring, A., Wallwork, K., Brugger, J., Kolitsch, U. (2006) Paratooite-(La), a new lanthanum-dominant rare-earth copper carbonate from Paratoo, South Australia. Mineralogical Magazine, 70, 131-138
  6. ^ Mindat, Paratooite-(La), https://www.mindat.org/min-27579.html
  7. ^ Handbook of Mineralogy, Paratooite-(La), http://www.handbookofmineralogy.org/pdfs/paratooite-(La).pdf
  8. ^ Krivovichev, S.V., Panikorovskii, T.L., Zolotarev, A.A., Bocharov, V.N., Kasatkin, A.V., Škoda, R. (2019) Jahn-Teller distortion and cation ordering: The crystal structure of paratooite-(La), a superstructure of carbocernaite. Minerals, 9, 370
  9. ^ Burke, E.A.J., Kampf, A. (2008) The use of suffixes is mineral names. Mineral Matters, in: Elements, 96; http://elementsmagazine.org/archives/e4_2/e4_2_dep_mineralmatters.pdf, visited 21.12.2019