The structure of amethyst quartz and the origin of its pleochroism C. V. RamanA. Jayaraman OriginalPaper Pages: 189 - 195
On the pleochroism of amethyst quartz and its absorption spectra S. Pancharatnam OriginalPaper Pages: 196 - 210
Some illustrations of the optical behaviour of iridescent calcite A. K. Ramdas OriginalPaper Pages: 217 - 219