gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1994.58A.2.97 Role of Microtexture in Isotopic Exchange and Weathering in Alkali Feldspars Parsons I. Lee M. R. Waldron K. A. David F. Walker L. Department of Geology and Geophysics, The University of Edinburgh, West Mains Road, Edinburgh, EH9 3JW, UK Burgess R. Isotope Geology Unit, Scottish Universities Research and Reactor Centre, East Kilbride, Glasgow, G75 0QU, UK Brown W. L. CNRS-CRPG, BP 20, F-54501 Vandoeuvre-lès-Nancy Cedex, France August–September 1994 58A 2 690 691 Copyright © 1994, The Mineralogical Society 1994