The overall format of previous editions has been maintained and new information has been incorporated in a similar style. This edition has two new chapters, on the manufacture and enhancement of gemstones and the old chapter on the detection of synthetic,
Collecting, handling and housing gemstones; refractive index and its measurement; double refraction and dispersion; colour, colour filters and the dichroscope; the specific gravity of gemstones and how to measure it; the use of the microscope; the manufac