Results from earlier laboratory studies are used to estimate the density of rime ice in laboratory simulations of thunderstorm microphysics and electrification. Comparisons of results in the works of Takahashi <1978>, Jayaratne et al. <1983>, and Saunders et al. <1991> show that kernel and opaque rime (&rgr;>0.33 g/cm3) are prevalent in the former study, whereas low-density feather rime (&rgr;<0.33 g/cm3) is prevalent in the latter studies. It is suggested that rime density may affect the charging process by either susceptibility to surface fracture on collision or impact of surface roughness on heat and vapor transfer at the ice surface. ¿ American Geophysical Union 1996