The diffusion of Y was measured in natural fluorite under dry 1atm conditions. The source of diffusant consisted of mixtures of Y fluorides 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 relation was:

D(m2/s) = 1.2 x 102 exp[-454(kJ/mol)/RT]

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