Diffusion of the rare earth in natural and synthetic fluorapatite was characterized under anhydrous conditions. In-diffusion experiments were performed, in which apatite was immersed in reservoirs of synthetic REE apatite analogs of various compositions.

At 800 to 1250C, the Arrhenius relationship was:

D(m2/s) = 2.6 x 10-7 exp[-324(kJ/mol)/RT]

D.J.Cherniak: Geochimica et Cosmochimica Acta, 2000, 64[22], 3871-85