A mineralogical study of a natural pyrophyllite

International audienceA chemical and mineralogical investigation of a Moroccan pyrophyllite is presented. X-ray powder diffraction has been largely used for phase identification and crystal symmetry determination. It is shown that this mineral has a triclinic symmetry with cell parameters: a = 5.160 Angstrom, b = 8.993 Angstrom, c=9.360 Angstrom, alpha=90.77 degrees, beta=100.57 degrees, and gamma=89.71 degrees. (C) 2000 International Centre for Diffraction Data. [S0885-7156(99)00403-0]