Decay index of Si II versus the decay index of Fe II for SNe from the Gold, Silver, and Bronze samples. The decay indices have been taken from either the power law (PL) slope or the pre-break slope for a broken power law (BPL) fit. For the majority of SNe, the silicon velocity decreases more rapidly than the iron velocity. There appears to be no significant differences between GRB-SNe and ordinary type Ic-BL SNe in this regard. For broken power laws, the decay index of the first segment is plotted.