Original paper

Burpalite, a new mineral from Burpalinskii massif, North Transbajkal, USSR: its crystal structure and OD character

Merlino, Stefano; Perchiazzi, Natale; Khomyakhov, Alexander P.; Pushcharovskii, D.Y.; Kulikova, I.M.; Kuzmin, V.I.

European Journal of Mineralogy Volume 2 Number 2 (1990), p. 177 - 186

16 references

published: Apr 17, 1990
manuscript accepted: Nov 24, 1989
manuscript received: Jul 10, 1989

DOI: 10.1127/ejm/2/2/0177

BibTeX file

ArtNo. ESP147050202004, Price: 29.00 €

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Abstract

Abstract Burpalite, a new mineral of the cuspidine-wohlerite-lävenite family, was found in a fenitized sandstone in the western contact zone of the Burpalinskii alkaline massif, North Transbajkal, USSR. Burpalite, with idealized chemical formula Na2CaZrSi2O7F2 is monoclinic, space group P21/a, Z = 4, a = 10.1173(8), b = 10.4446(6), c = 7.2555(3) Å, β= 90.039(7)°. It occurs as colourless platy crystals up to 1 × 3 × 5 mm, with vitreous lustre. Moris' hardness is 5-6 ; the density is 3.33(15) g/cm3. Optically, burpalite is biaxial negative with 2V = 82(1)° and nα = 1.627(2),nβ = 1.634(2), nγ = 1.639(2). The strongest lines in the powder pattern (d in A, intensity in parentheses) are: 2.962 (vs), 1.787 (s), 1.886 (ms), 1.556 (ms), 3.306 (m), 3.035 (m). The space group symmetry and cell parameters of burpalite pointed to one of the ten possible structure types derived by Merlino & Perchiazzi (1988) for the cuspidine-wohlerite-lävenite family. This was confirmed by structure refinement to a final R of 0.067. The OD character of burpalite is described, and the relationships between burpalite and “orthorhombic làvenite” are discussed.

Keywords

Keywords burpalitenew mineralcrystal structurecuspidine familyOD theory