• journal_title：European Journal of Mineralogy
• Contributor：Ritsuro Miyawaki ; Kazumi Yokoyama ; Tomas A. Husdal
• Publisher：E. Schweizerbart'sche Verlagsbuchhandlung Science Publishers
• Date：2013-02-01
• Format：text/html
• Language：en
• Identifier：10.1127/0935-1221/2013/0025-2265
• journal_abbrev：Eur J Mineral
• issn：0935-1221
• volume：25
• issue：2
• firstpage：187
• section：Articles

Bastnäsite-(Nd), ideally (Nd,La,Ce)(CO₃)F, occurs in the Stetind pegmatite, Tysfjord, Nordland, Norway, in association with bastnäsite-(Ce), calcioancylite-(Nd) and/or kozoite-(Nd), stetindite, vyuntspakhkite-(Y) and Y-bearing fluorite. It forms 20 μm wide zones in outer parts of tabular bastnäsite-(Ce) crystals. Bastnäsite-(Nd) is translucent and is pale purplish pink to colourless with a vitreous, greasy or pearly lustre. Bastnäsite-(Nd) has a Mohs hardness of 4–4½, is brittle, and shows an indistinct cleavage on {101̄0} and an uneven fracture. The calculated density and mean refractive index are 5.23 g cm⁻³ and 1.76, respectively. It is hexagonal, space group P6̄2c, a = 7.0792(13), c = 9.721(2) Å, V = 421.92(18) ų and Z = 6. The five strongest lines in the powder XRD pattern are [d(Å), I/I₀, hkl]: 4.86, 71, 002; 3.54, 70, 110; 2.86, 100, 112; 2.04, 31, 300 and 2.00, 48, 114. The electron-microprobe analyses lead to the empirical formula (on the basis of M = C = 1 apfu): Nd_0.353La_0.253Ce_0.251Pr_0.086Sm_0.037Gd_0.016Y_0.004Dy_0.001CO_2.978F_1.044. Bastnäsite-(Nd) is a member of the bastnäsite group, and is the Nd-dominant analogue of bastnäsite-(Ce), bastnäsite-(La) and bastnäsite-(Y). Bastnäsite-(Nd) formed as a late phase in cavities in Y-bearing fluorite, which in turn is a late formation of the pegmatite.