Home > Mineral Abstracts > CanMin Vol. 27, pp. 125-127 (1989)




Vol. 27, pp. 125-127 (1989)



Griceite, LiF, a new mineral species
from Mont Saint-Hilaire, Quebec


Jerry van Velthuizen
Mineral Sciences Division,
National Museum of Natural Sciences,
Ottawa, Ontario K1P 6P4



G. Y. Chao
Ottawa-Carleton Centre for Geoscience Studies,
Department of Earth Sciences,
Carleton University, Ottawa , Ontario K1S 5B6


ABSTRACT

          Griceite, ideally LiF, a new mineral species from the Poudrette quarry, Mont Saint-Hilaire, Quebec, occurs in sodalite inclusions near the periphery of massive hornfels in association with ussingite, analcime and villiaulite.  Griceite is bright to dull white, inclining to pale yellow, and occurs as fine-grained botyroidal aggregates, as fine-grained powders, as irregular (~0.1 to 1.0mm) inclusions in villiaumite, and as possible pseudomorphs displaying pseudotetragonal or pseudomonoclinic symmetry.  Griceite is translucent to opaque with a dull to vitreous luster, white streak, hardness ~ 4.5, and good {100} cleavage.  A few specimens display uneven to conchoidal fracture.  Griceite is isotropic, n 1.3986 (5), and fluoresces light yellow in shortwave ultraviolet in some specimens.  By analogy with synthetic LiF, griceite is cubic, space group Fm3m.  The refined unit-cell parameter a is 4.0293 (2) Å,
V 65.415 (9) Å3 .  The strongest three X-ray powder-diffraction lines [d in Å(I)(hkl)] are:

2.324 (9)(111)
2.013 (10)(200)
1.414 (5)(220)

     Wet-chemical analysis gave:

Li - 24.72
F - 72.20
Al - 0.06

Ca - 0.03
Mn - 0.01
Fe - 0.03

     Total 97.05 wt.%, corresponding to Li0.97F1.03, ideally LiF; Dmeas 2.62, Dcalc 2.67 g/cm3, with Z = 4.  Griceite is named for Joel Denison Grice, Curator of Minerals, National Museum of Natural Sciences in Ottawa.

Keywords:  griceite, Poudrette quarry, Mont Saint-Hilaire, Quebec, lithium fluoride, new mineral species, X-ray data, chemical analysis.


© 1989  The Canadian Mineralogist