Comminution of silicon is a necessary conditioning step for the Direct Synthesis of the primary monomer to the silicone polymers and is critical at least for subsequent powder processing if not for chemical activity. Peculiarities of the fine and superfine particles produced during the grinding of Metallurgical-Grade silicon are investigated, giving insights of their generation mechanisms during grinding. The fracture of silicon appears to be purely brittle at all scales and mainly transgranular, despite the presence of intergranular silicides. Yet, the properties of the particles are not homogeneous over the particle size ranging from about 500 µm to 0.1 µm. Fines and superfines exhibit specific behaviours: the chemical composition is the same in the coarser fractions but increases for 20-60 µm particles and dramatically falls down for particles smaller than 10 µm. The crystal lattice is unchanged during grinding except for particles smaller than 1 µm where partial amorphization is observed and could be due to high stresses experienced by these particles during interparticular friction. Measurement of the mechanical properties of intergranular silicides was undertaken using nanoindentation and shows silicides have different properties, what should be linked to the low concentration of impurities in the finer fractions of the ground powder. For further understanding of the fragmentation mechanisms, laboratory scale batch grinding are undertaken: first tests show deviations to the first-order population balance model associated with fines influence on grinding kinetics.