Publication Type:

Journal Article

Authors:

McDonald, Andrew M.; Chao, George Y.

Source:

The Canadian MineralogistThe Canadian Mineralogist, Mineralogical Association of Canada, Ottawa, ON, Canada, Volume 39, Part 5, p.1295-1306 (2001)

ISBN:

0008-4476

Keywords:

Canada, chemical composition, concentration, crystal chemistry, crystal form, crystal structure, eastern canada, formula, granites, hydration, igneous rocks, infrared spectra, mineral composition, Mont-Saint-Hilaire Quebec, new minerals, optical properties, Pegmatite, petrography, physical properties, plutonic rocks, quebec, Rouville County Quebec, silicates, spectra, x-ray diffraction data

Abstract:

Natrolemoynite occurs in pegmatites cutting nepheline syenite at the Poudrette quarry, Mont Saint-Hilaire; it is associated, in altered pegmatites, with microcline, lemoynite, lepidocrocite, galena, sphalerite, calcite and pyrite, and in unaltered pegmatites, with biotite, microcline, albite, magnetite, a chlorite-group mineral, a burbankite-group mineral, an unidentified donnayite-(Y)-like mineral, zircon and pyrochlore. Crystals (1 X 2 mm) are colourless to white, bladed to prismatic, elongated on [001] with perfect 100 and 010 cleavage; they typically form radial aggregates and spheres < or = 4 mm; H. 3, D 2.47 g/cm (super 3) ; alpha 1.533, beta 1.559, gamma 1.567, 2V (sub alpha ) 63 degrees , dispersion is weak with r and v crossed; orientation alpha = b, gamma :a = 41 degrees (in obtuse angle beta ). EPMA gave SiO (sub 2) 54.51, TiO (sub 2) 0.38, ZrO (sub 2) 21.97, Nb (sub 2) O (sub 5) 1.01, Al (sub 2) O (sub 3) 0.04, MnO 0.12, CaO 0.37, Na (sub 2) O 7.47, K (sub 2) O 1.29, H (sub 2) O (sub calc) 14.72, = 101.88, corresponding with an ideal formula of Na (sub 4) Zr (sub 2) Si (sub 10) O (sub 26) .9H (sub 2) O. Indexed XRD powder data are tabulated; strongest lines 8.132(100), 5.975(4), 3.564(40), 3.974(35), 3.490(35) Aa; a 10.5150, b 16.2534, c 9.1029 Aa, beta 105.462 degrees , V 1499.4 Aa (super 3) ; space group C2/m, Z = 4. The structure was refined to R 4.2% and has six-membered rings of SiO (sub 4) tetrahedra linked along [001] by ZrO (sub 6) octahedra to form a zirconosilicate framework; channels [001] are occupied by Na and H (sub 2) O. Natrolemoynite is one of the last sodium zirconosilicate hydrate phases to develop.

Notes:

GeoRef, Copyright 2018, American Geological Institute.<br/>2002-034160<br/>lemoynite<br/>natrolemoynite<br/>Poudrette Quarry<br/>zirconosilicates