Home > Mineral Abstracts > CanMin Vol. 29, pp. 107-111 (1991)




Vol. 29, pp. 107-111 (1991)



Rouvilleite, a new sodium calcium fluorocarbonate mineral
from Mont Saint-Hilaire, Quebec


Andrew M. McDonald and George Y. Chao
Ottawa-Carleton Geoscience Centre, Department of Earth Sciences,
Carleton University, Ottawa , Ontario K1S 5B6



Robert A. Ramik
Department of Mineralogy, Royal Ontario Museum,
100 Queen's Park, Toronto, Ontario M5S 2C6


ABSTRACT

     Rouvilleite, ideally Na3Ca2(CO3)3F, is a new mineral species from Mont Saint-Hilaire, Quebec.  The mineral is transparent to translucent and occurs as tan, rusty brown and colorless crystalline masses, and rarely as transparent euhedral crystals, in an inclusion of sodalite syenite in nepheline syenite.  Crystals are prismatic, elongate along [001], and are either terminated by {001} or by {101}, {023} and {032}.  Associated minerals include villiaumite, shortite, aegirine, microcline, cancrinite, analcime, vuonnemeite, cryolite, kogarkoite and others.  Rouvilleite is brittle, Mohs hardness about 3, with a vitreous to slightly waxy luster, a white streak, an uneven fracture and imperfect {010} and good {001} cleavages.  The mineral effervesces vigorously in 1:1 HCl and does not show fluorescence in ultraviolet light.  It is optically biaxial negative with a 1.472(1), b 1.562(1), g 1.569(1), 2Vmeas 25(1)°, 2Vcalc 30°, and a weak dispersion r > v.  The orientation is b = Y, c & X = 6° in the acute b angle.  Rouvilleite is monoclinic, Cc or C2/c, with a 8.043(4), b 15.812(5), c 7.030(3) Å, b = 101.16(3)°, V 877.1(4) Å3 and Z = 4.  The strongest six lines of the X-ray diffraction pattern (Gandolfi) [d in Å (I)(hkl)] are:

7.081 (80)(110)
2.937 (70)(150)
2.895 (100)(202)

2.711 (90)(222)
2.039 (70)(242)
1.869 (75)(352)


     Averaged results of electron-microprobe analyses give:

Na2O - 25.95
CaO - 26.47
MnO - 6.83
FeO - 0.52

MgO - 0.52 0.01
F - 5.65
CO2 -- [37.21] (calc.)
-F - 2.38


     Sum 100.26 wt.%, corresponding to


Na2.97(Ca1.67Mn0.34Fe0.02)S2.03(CO3)3F1.06.

Infrared-absorption spectroscopy confirms the presence of CO2Dmeas. 2.67(2), Dcalc. 2.69 g/cm3.  The name recalls Rouville county, within which Mont Saint-Hilaire occurs.

Keywords:  rouvilleite, new mineral species, sodium calcium fluorocarbonate, Mont Saint-Hilaire, Quebec, X-ray data, chemical composition.


© 1991  The Canadian Mineralogist