Order and disorder in feldspar

Forelesninger holdt ved Advanced Study Institute of Feldspar - Oslo 1962
Lectures held at Advanced Study Institute of Feldspar - Oslo 1962

This paper will be concerned with relations between order and disorder from the structural viewpoint, and will draw its evidence almost entirely from the results of X-ray diffraction. Optical properties are left out, partly for lack of room, partly because so little is really known about their interpretation in terms of atomic environments and interatomic forces. Moreover, because the wavelength of light is so much longer than that of X-rays, the effects measured by optical experiments represent averages over very much larger volumes than those which can be resolved by X-rays (cf.ยง 2). Again, thermodynamic studies, by their nature, represent averages over large enough volumes to treat statistically, and therefore are of limited use for the problems here considered.