Summary
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]
| Paratooite-(La) | |
|---|---|
 Paratooite-(La): Locality: Paratoo copper mine, Yunta, Olary Province, South Australia, Australia. Field of view 6 mm. | |
| General | |
| Category | Carbonate mineral |
| Formula (repeating unit) | (La,Sr,Ca)4CuCa(Na,Ca)2(CO3)8 |
| IMA symbol | Pto-La[1] |
| Strunz classification | 5/B.0; 5.AD.20 (Nickel-Strunz) |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal: mmm |
| Space group | Pbam |
| Unit cell | a = 7.2250, b = 12.7626 c = 10.0559 [Å] |
| Identification | |
| Color | pale turquoise-blue to pale blue |
| Crystal habit | blades (sheaves) intergrown to form spray-like aggregates |
| Cleavage | {100} (possible) |
| Mohs scale hardness | 4 (probably) |
| Luster | vitreous or pearly |
| Streak | pale blue |
| Specific gravity | 1.97-2.02 (measured) |
| Optical properties | biaxial negative, α = 1.605(3), β = 1.696(3), γ = 1.752(2) |
| Pleochroism | moderate, very pale blue (X) to greenish blue (Y = Z) |
| 2V angle | 72.6 ° |
| References | [2][3][4] |
References edit
- ^ 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.
- ^ 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
- ^ Mindat, Paratooite-(La), https://www.mindat.org/min-27579.html
- ^ Handbook of Mineralogy, Paratooite-(La), http://www.handbookofmineralogy.org/pdfs/paratooite-(La).pdf
- ^ 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
- ^ Mindat, Paratooite-(La), https://www.mindat.org/min-27579.html
- ^ Handbook of Mineralogy, Paratooite-(La), http://www.handbookofmineralogy.org/pdfs/paratooite-(La).pdf
- ^ 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
- ^ 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