Mineralogy and Crystal Structure of Greenalite

GREENALITE, a hydrous ferrous silicate, was first described in detail by Leith1; heavy contamination by other constituents of the iron-ore in which it occurred made analysis difficult. Discrepancies between analyses of the mineral by Leith and by Jolliffe2were ascribed by Gruner3to different methods of correcting for insoluble silica. Gruner found the X-ray pattern to be very similar to that of chrysotile, but different from chlorite, micas and chamosite. Gruner ascribed to greenalite a unit cell similar to chrysotile, although he found it impossible to tell whether the β-angle differed from that of chrysotile, 93° 16′. Gruner's analysis corresponded to a structural formula of Fe2+4.5Fe3+1.0(Si4O10)(OH)8.