Tracer diffusion was studied in natural and synthetic single crystals of diopside, using stable tracers enriched in 54Fe, at 950 to 1100C, under 1atm. The diffusion profiles were determined by using an ion microprobe. For directions parallel to the c-axis and the b-axis of two natural low-iron (∼1.8at%) diopsides, the data obeyed a single relationship:

D(m2/s) = 6.22 x 10-15 exp[-161.5(kJ/mol)/RT]

F.Azough, R,Freer:  Physics and Chemistry of Minerals, 2000, 27[10], 732-40