gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1979.043.327.05 Two New Occurrences and the Gibbs Energy of Burkeite Vergouwen Lideke Department of Soil Science and Geology, Agricultural University, PO Box 37, Wageningen, The Netherlands 9 1979 43 327 341 345 30 10 1978 Copyright © 1979, The Mineralogical Society 1979 Summary

Burkeite (Na6CO3(SO4)2) is found as a surface mineral in the north of Kenya associated with thenardite and halite and in the Konya basin in Turkey associated with trona and halite. The cell dimensions of a natural burkeite are a = 7.070, b = 9.220, c = 5.173 Å. The Gibbs energy of burkeite is estimated in relation to other sodium carbonates and sulphates. Δ ΔGf,298.15° (burkeite) = 3594.2 ± 3 kJ.