The diffusion of Mn was characterized using Rutherford back-scattering spectrometry. An Arrhenius relationship was obtained for Mn diffusion in natural Durango fluorapatite, for diffusion parallel to c:

D(m2/s) = 5.4 x 10-7 exp[-288(kJ/mol)/RT]

The Mn diffusion normal to c appeared to be similar to diffusion parallel to c, and diffusivities in natural and synthetic (free of significant amounts of rare earth or other minor constituents) samples were the same, within experimental error. Experiments which were run in air, where Mn was in a more oxidized state, yielded diffusivities similar to those for experiments run in sealed silica capsules, given by above relationship.

D.J.Cherniak: Chemical Geology, 2005, 219[1-4], 297-308