Home > Mineral Abstracts > Can Min Vol. 18, pp. 85-88 (1980)




Vol. 18, pp. 85-88 (1980)



Paranatrolite, a new zeolite from
Mont St-Hilaire, Québec


George Y. Chao
Department of Geology, Carleton University,
Ottawa , Ontario K1S  5B6


ABSTRACT

     Paranatrolite, a new zeolite from Mont St-Hilaire, Québec, is unstable in air and dehydrates to form tetranatrolite.   Unaltered paranatrolite has been observed only as colorless transparent epitactic overgrowths on natrolite crystals preserved in water since the time of collection.   Physical properties are :  H = 5-5½, D(obs) = 2.21 g/cm3; fracture conchoidal; cleavage, unobserved.  The mineral is pseudo- orthorhombic, diffraction aspect, F***, with a 19.07(1), b 19.13(1), c 6.580(3) Å, Z = 8.  The true symmetry is probably monoclinic, perhaps triclinic.  The diffraction spots are very diffuse, suggestive of a disordered structure.  The strongest Gandolfi diffraction lines are:

6.76 (20)(220)
5.92 (60)(111)
4.78 (30)(040,400)

4.44 (40)(131,311)
3.26 (15)(151,511)
3.12 (15)(022,202)

2.94 (100)(351,531)
2.65 (15)(460,640)
2.51 (15)(171,711)

1.772 (15)(3.10.0,   10.4.0)


     The powder pattern is similar to that of gonnardite.  Optically the mineral is biaxial negative, 2V < 10°, with low birefringence and oblique extinction.   The chemical formula is that of tetranatrolite except for the water content, which is calculated from the mass-density-volume relationship: (Na1.75Ca0.40>K0.09)Fe0.01Al1.95Si3.02O10 · 2.98H2O.

Keywords:  paranatrolite, Mont St-Hilaire, Qu├ębec, tetranatrolite, zeolite, gonnardite.



© 1980  The Canadian Mineralogist