Descriptive section: inorganic materials

Abstract

Throughout the descriptive section the chemical composition, crystal system, physical properties and other data are given in the same order for each species. Mineral families such as corundum and beryl are described as families so that ruby must be sought under corundum and emerald under beryl. In order to avoid overloading the text with figures which have no more than academic significance, I have not provided items such as dispersion for more than a few species in which this property is important.