gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1979.043.325.21 Short Communications Hornblende Twinning on (1¯01) in an Amphibolite from Barra, Outer Hebrides, Scotland Sobott R. J. G. Mineralogisch-Petrographisches Institut der Universität Heidelberg, Im Neuenheimer Feld 236, D-6900 Heidelberg i, W. Germany 3 1979 43 325 177 178 12 9 1978 Copyright © 1979, The Mineralogical Society 1979