These images illustrate the replacement of clinopyroxene by amphibole (hornblende).  The clinopyroxene in the core is pale green and has slightly higher relief than the surrounding amphibole, which is darker green in plane light (A).  Under crossed nicols (B), the enclosing amphibole can be seen to consist of two grains, one pale first order yellow (in the lower left corner) and the other with first order white interference colours (masked by the absorption colours), which surrounds the first order yellow clinopyroxene.  The ragged margins of the clinopyroxene and the presence of isolated “islands” of clinopyroxene that are in optical continuity with the core, suggest that the clinopyroxene was consumed during amphibole formation.  This relationship probably resulted from late hydrous magmatic fluids reacting with pre-existing clinopyroxene to form amphibole.  It could also be due to a hydrothermal overprint, however, unrelated to the formation of the original igneous assemblage.  These images are of a hornblende syenite from Avery County, North Carolina.  Fields of view are 2.2 mm across.  A ppl, B x-nicols.