Free UK postage
Strahan, A. et al. (1916). Special Reports on the Mineral Resources of G.B.: Vol. V- Potash-Felspar – Poasphate of Lime – Alum Shales. British Geological Survey.
Viljoen, M.J. and Reimold, W.U. (1999). An Introduction to South Africa’s Geological and Mining Heritage. Mintek.
Webster, R. (1962). Gems; Their Sources, Descriptions and Identification. London: Butterworths. Butterworth.
Weibel, M (1966). A Guide to the Minerals of Switzerland. London: John Wiley, 123 + xi pp. 24 colour plates. Hardback,. John Wiley.