Titre du document / Document title
Mg-deficient strontium benstonite from the ore occurrence biraya (Siberia)
Auteur(s) / Author(s)
KONEV A. A. ;
KARTASHEV P. M. ;
KONEVA A. A. ;
USHCHAPOVSKAYA Z. F. ;
NARTOVA N. V. ;
Résumé / Abstract
For the first time, there is characterized the Mg-deficient strontium benstonite from Birainskoye occurrence (in Irkutsk region), where the mineral occurs as an accessory one in host fenites, but makes up to 35 % in composition of some hydrothermal veins. Chemical composition of benstonite itself is considerably varying, it allows to distinguish five its varieties, and two among them are represented in veins as the main minerals: (Ba
3.25Sr
2.75)
6.00(Ca
5.42Sr
0.36(La
0.13Ce
0.07Pr
0.01Nd
0.01)
0.22)
6.08(Ca
0.50Mg
0.33Fe
0.05Mn
0.02)
0.90 [CO
3]
13(Ba
4.20Sr
1.80)
6.00(Ca
5.74Sr
0.24La
0.02)
4.00(Mg
0.51Ca
0.29Fe
0.09Mn
0.94)
0.93[CO
3]
13. The standard and Mg-free benstonite and its varieties with Sr prevailing over Ba are developed in minor and accessory amounts. Optical constants and physical data for Mg-deficient strontium benstonite: density 3.56 (1) g/cm
3; No = 1.687 (1); Ne = 1.526 (5); the strongest X-ray powder diffraction lines [d in A (I) (hkl)]: 3.08 (100) (312); 3.03 (20) (330); 3.17 (12) (050); 2.12 (12) (621); 3.89 (10) (131); 2.53 (10) (250). Unit cell parameters: a = 18.21 (0.01) A; c = 8.67 (0.01) Å; V= 2491 (4) Å
3. IR spectra and thermogravimetric curves are the same as the standard ones. Unlike the Murunsky strontium benstonite which doesn't contain Mg but is enriched in Ca, the Birainsky Mg-deficient benstonite is characterized by the normal Ca contents.
Revue / Journal Title
Zapiski Vserossijskogo mineralogičeskogo obŝestva
ISSN 0869-6055
Source / Source
2004, vol. 133, n
o6, pp. 65-73 [9 page(s) (article)]
Langue / Language
Russe
Editeur / Publisher
Nauka, Sankt-Peterburg, RUSSIE, FEDERATION DE
(1992)
(Revue)
Localisation / Location
INIST-CNRS, Cote INIST : 4673, 35400013476271.0050
Nº notice refdoc (ud4) : 17406183
