Titre du document / Document title

Novgorodovaite Ca²(C²O⁴)Cl² 2H²O, a new mineral

Auteur(s) / Author(s)

CHUKANOV N. V. ; BELAKOVSKII D. I. ; RASTSVETAEVA R. K. ; KARIMOVA O. V. ; ZADOV A. E. ;

Résumé / Abstract

A new oxalate mineral novgorodovaite has been found in evaporite rock from Chelkar salt dome, W. Kazakhs-tan. It occurs as aggregates of colourless grains (up to 7 mm) together with anhydrite, gypsum, halite, bischofite, magnesite, hilgardite. Cleavage medium on (100) and (010); Mohs hardness 2.5, brittle, optically biaxial, negative, α1.565(2), β 1.645(2), γ 1.725(4), 2V^mcas = 88(10); D^mcas = 2.38(1) g/cm₃; D^calc = 2.40(2)g/cm₃. The crystal structure is solved, R=0.029. Monoclinic, l1 2/m 1, a=6.936(3),b=7.382(3), b=7.443(3)Å, V=380.0(2). β=94.3(1)°, V=380.0(2)Å₃, Z= 2. Chemical composition (wt %): Ca 29.43, Cl 24.56 (electron microprobe); C 8.53, H 1.67 (selective, sorption of combustion products in oxygen). Empirical formula: Ca^2.00(C²O⁴)^0.97Cl^1.89(OH)^0.17 2.17 ŲO. The strongest lines of X-ray powder diffraction pattern d. Å (l, hkl) are: 5.062(7,110),4.812 (5,103), 4.323(7,11-1), 4.063(7, 111), 3.644 (5, 020), 2.956(8, 21-1), 2.917 (10, 112). IR specrtum is given. The mineral is named after well know mineralogist, director of Fersman Mineralogical Museum of Russian Academy of Sciences, Margarita Ivanovna Novgorodova (b.1938). The specimens of novgorodovaite are deposited at Fersman Mineralogical Museum of Russian Academy of Sciences. Moscow.

Revue / Journal Title

Zapiski Vserossijskogo mineralogičeskogo obŝestva   ISSN 0869-6055 

Source / Source

2001, vol. 130, n^o4, pp. 32-35 [4 page(s) (article)]

Langue / Language

Russe

Editeur / Publisher

Nauka, Sankt-Peterburg, RUSSIE, FEDERATION DE  (1992) (Revue)

Localisation / Location

INIST-CNRS, Cote INIST : 4673, 35400010325950.0040