IMA 2017-084 = lasnierite

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 26001
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

IMA 2017-084 = lasnierite

Messaggio da Marco E. Ciriotti » lun 17 dic, 2018 11:39

Prossima pubblicazione.

Referenza:
▪ Rondeau, B., Devouard, B., Jacob, D., Roussel, P., Stéphant, N., Boulet, C., Mollé, V., Corre, M., Fritsch, E., Ferraris, C., Parodi, G.C. (2019): Lasnierite, (Ca,Sr)(Mg,Fe)2Al(PO4)3, a new phosphate accompanying lazulite from Mt. Ibity, Madagascar: an example of structural characterization from dynamical refinement of precession electron diffraction data on submicrometer sample. European Journal of Mineralogy, 31, (in press).
Marco E. Ciriotti

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

Avatar utente
Marco E. Ciriotti
Messaggi: 26001
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2017-084 = lasnierite

Messaggio da Marco E. Ciriotti » mer 22 mag, 2019 10:22

Pubblicazione effettuata.

Referenza:
▪ Rondeau, B., Devouard, B., Jacob, D., Roussel, P., Stéphant, N., Boulet, C., Mollé, V., Corre, M., Fritsch, E., Ferraris, C., Parodi, G.C. (2019): Lasnierite, (Ca,Sr)(Mg,Fe)2Al(PO4)3, a new phosphate accompanying lazulite from Mt. Ibity, Madagascar: an example of structural characterization from dynamical refinement of precession electron diffraction data on submicrometer sample. European Journal of Mineralogy, 31, 379-388.

Abstract:
Lasnierite, (Ca,Sr)(Mg,Fe)2Al(PO4)3, is a new phosphate mineral from Mt. Ibity, close to Itremo, central Madagascar. The mineral was found as inclusions accompanying blue lazulite and many other minerals in blue metaquartzite occasionally used as a gemstone or ornamental stone. The crystals were very small and embedded in quartz so that they could not be extracted mechanically, precluding any “classical” X-ray diffraction on either single-crystal or powder sample. Hence, Focused Ion Beam (FIB) lamellae were extracted and the structure was successfully solved and refined using the recently proposed method of precession electron diffraction tomography (PEDT) associated to dynamical refinement. This underlines the efficiency of this new method for defining mineral species on volumes too small to be manipulated by classical means of X-ray diffraction. Accompanying minerals include various phosphates, sulfates, oxides and silicates. Lasnierite occurs as transparent, near-colourless bladed crystals up to 120 × 60 μm in section. Only five crystals have been identified yet in our samples. The empirical formula, based on wavelength dispersive spectrometry (WDS) electron microprobe analyses and calculated on 12 (O+F) atoms per formula unit, is (Ca0.59Sr0.37)∑0.96(Mg1.42Fe0.54)∑1.96Al0.87(P2.99Si0.01)∑3.00(O11.41F0.59)∑12. LA-ICPMS shows that concentrations of Li, Be and B are below the detection limit. The calculated density based on the empirical formula is 3.162 g cm−3. Lasnierite is orthorhombic, space group Pbcn, with unit-cell parameters: a = 6.2771(3) Å, b = 17.684(3) Å, c = 8.1631(4) Å, Z = 4 and V = 906.1(2) Å3. The structure is new. The Raman spectra show characteristic peaks at 99, 122, 278, 418, 510, 569, 590, 621, 661, 985, 1028, 1040, 1063, 1100, 1126 and 1148 cm−1 (most intense bands are italicised). Raman spectra also show the absence of H2O and CO2.
Marco E. Ciriotti

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

Rispondi

Chi c’è in linea

Visitano il forum: Bing [Bot] e 2 ospiti