The results for cubic crystals, at 100 to 400C, could be described by:

D (cm2/s) = 3.0 x 10-5 exp[-9.4(kcal/mol)/RT]

while those for plate crystals, at 100 to 400C, could be described by:

D (cm2/s) = 2.5 x 10-6 exp[-3.1(kcal/mol)/RT]

A.Y.Kupryazhkin, P.V.Volobuev, P.E.Suetin: Zhurnal Fizicheskoi Khimii, 1975, 49[2], 546-7