IMA 2022-008 = gysinite-(La)

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Marco E. Ciriotti
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IMA 2022-008 = gysinite-(La)

Messaggio da Marco E. Ciriotti » lun 21 nov, 2022 17:11

Prossima pubblicazione.

Referenza:
▪ Wu, B., Gu, X., Rao, C., Wang, R., Xing, X., Wan, J., Zhong, F., Bonnetti, C. (2023): Gysinite-(La), LaPb(CO3)2(OH)⋅H2O, a new rare earth mineral of the ancylite group from the Saima alkaline complex, Liaoning Province, China. Mineralogical Magazine, 87, (in press).

Abstract:
The new mineral, gysinite-(La), with the ideal formula LaPb(CO3)2(OH)·H2O, has been discovered in lujavrite from the Saima alkaline complex, Liaoning Province, China. It commonly occurs as subhedral to anhedral, granular and platy crystals of 5 to 50 μm in size, in interstices or enclosed in microcline, aegirine and nepheline. Associated minerals include nepheline, aegirine, microcline, natrolite, eudialyte, lamprophyllite, bastnäsite-(Ce), parasite-(Ce), ancylite-(La), ancylite-(Ce), bobtraillite, britholite-(Ce), thorite, calcite and galena. The crystallization of gysinite-(La) may be related to the post-magmatic carbonation event. Gysinite-(La) crystals are generally transparent, colourless, or pale yellow, with a vitreous lustre and white streak. It is brittle with an uneven fracture, and the estimated Mohs hardness is 3½ to 4. The calculated density is 5.007 g/cm3. Optically, gysinite-(La) is biaxial (–), α= 1.832(2), β= 1.849(4), γ = 1.862(5) in white light, and 2Vmeas = 81.6°. The empirical formula of gysinite-(La) is (La0.93Pb0.61Nd0.23Pr0.14Sr0.04Gd0.02Sm0.01Eu0.01Ca0.01)Σ2(CO3)2(OH)1.34·0.66H2O, which is calculated on the basis of general formula (REExM2+2-x)(CO3)2(OH)x(2-x)H2O. The strongest eight lines of its powder XRD pattern [d, Å (I, %) (hkl)] are: 5.596 (21)(011), 4.349 (100) (110), 3.732 (68) (111), 2.984 (61) (121), 2.667 (21) (031), 2.363(48) (131), 2.090 (29) (221), and 2.028 (21) (212). Gysinite-(La) is orthorhombic, in the space group Pmcn, and unit-cell parameters refined from single-crystal X-ray diffraction data are: a = 5.0655(2) Å, b = 8.5990(3) Å, c = 7.3901(4) Å, V = 321.90(2) Å3 and Z = 2. It is a new member of the ancylite group and isostructural with gysinite-(Nd), while the occupancies of La and Pb are dominant in the metal cation site in structure.

NdR: "parasite-(Ce)" = parisite-(Ce).
ancylite group
Ancylite-(Ce) SrCe(CO3)2(OH)·H2O
Ancylite-(La) SrLa(CO3)2(OH)·H2O
Calcioancylite-(Ce) CaCe3(CO3)4(OH)3·H2O
Calcioancylite-(La) CaLa(CO3)2(OH)·H2O
Calcioancylite-(Nd) Ca1.2Nd2.8(CO3)4(OH)3·H2O
Gysinite-(La) Pb2+La(CO3)2(OH)·H2O
Gysinite-(Nd) Pb2+Nd(CO3)2(OH)·H2O
Kozoite-(La) La(CO3)[(OH),H2O]
Kozoite-(Nd) Nd(CO3)[(OH),H2O]
Schuilingite-(Nd) Pb2+Cu2+Nd(CO3)3(OH)·1.5H2O
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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Marco E. Ciriotti
Messaggi: 31675
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2022-008 = gysinite-(La)

Messaggio da Marco E. Ciriotti » sab 18 feb, 2023 11:01

Pubblicazione effettuata.

Referenza:
▪ Wu, B., Gu, X., Rao, C., Wang, R., Xing, X., Wan, J., Zhong, F., Bonnetti, C. (2023): Gysinite-(La), LaPb(CO3)2(OH)⋅H2O, a new rare earth mineral of the ancylite group from the Saima alkaline complex, Liaoning Province, China. Mineralogical Magazine, 87, 143-150.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

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