The Balmuccia massif is dominantly lherzolitic. Dunites are a minor lithotype occurring: a) at the contacts of websterite dykes; b) as tabular bodies associated with layers of Cr-rich spinel; c) as large, decametric lenses typically associated with hornblendite pockets and veins. Type a dunites are 15 cm), olivine coexists with clinopyroxene. At a distance of 10-13 cm, clinopyroxene coexists with a “pyribole” (a mineral constituted by a few microns-large lamellae of clinopyroxene and amphibole). At 7-10 cm distance, clinopyroxene disappears and the pyribole coexists with discrete amphibole (kaersutite) crystals. Closer to the pocket, pyribole disappears and only amphibole and spinel (high Ti, low Cr) are present along with olivine. Similar variations occur in thin veins cutting the dunite and ending at the pocket. The pockets, up to 40 cm large, are constituted by giant kaersutitic amphibole, phlogopite, plagioclase, rutile, Al-Mg spinel. Towards the ambient lherzolites, the dunite fades into wehrlite, where orthopyroxene abundance increases outwards and the outer belt is constituted by a granular, undeformed, opx-rich lherzolite.On the basis of petrography, Sr and Nd isotopes and trace element characteristics of clinopyroxene we preliminarily hypothesise that type b dunites are the result of Cr-diopside dykes melting, eventually triggered by percolation of deeper-derived melts, and reactive percolation of these melts into the ambient lherzolite under increasing melt mass conditions. Type c dunites may represent a relatively shallow event (as indicated by the plagioclase stability) of reactive percolation of an hydrous, possibly alkaline, melt under decreasing melt mass.