The diffusion of Nd was measured in natural fluorite under dry 1atm conditions. The source of diffusant consisted of mixtures of rare-earth fluoride and CaF2 powders, pre-reacted in vacuo in silica glass tubes. Following diffusion annealing, concentration profiles were measured using Rutherford back-scattering spectroscopy. At 700 to 1050C, the Arrhenius relationship was:

D(m2/s) = 4.8 x 10-2 exp[-385(kJ/mol)/RT]

D.J.Cherniak, X.Y.Zhang, N.K.Wayne, E.B.Watson:  Chemical Geology, 2001, 181[1-4], 99-111