Cleavage of ionic minerals
Mineral cleavage can be resolved into two components: cleavability and optical effect. The electrical theory of matter in the solid state leads to a quantitative expression for the cleavability of ionic minerals C_(hkl) = A(hkl)/Σ_i n_i s_i cos θ_i. Approximate values for s are obtained by using the electrostatic bond strength. Systematic application to minerals whose constituent atoms have inert-gas cores gives good agreement with observation.
© 1936 Mineralogical Society of America. This research was greatly aided by a Storrow Fellowship in Geology of the National Research Council. I wish to thank Professor Linus Pauling for his kindly interest and advice throughout the investigation. I am also indebted to Gates Chemical Laboratory for research facilities.