Nature and Paragenesis of Asbestos Minerals [and Discussion]

The asbestos minerals fall into two groups of differing genetic, physical and chemical properties, their only common feature being their fibrous nature. Chrysotile is a sheet silicate, having a layered structure in the form of a scroll or ture, while the amphibole fibres are chain silicates with a lath-like structure. The biological effects of asbestos depend firstly on its ability to form very small fibres capable of aerial suspension, inhalation and subsequent deposition in the minutest airways of the lung; secondly on the texture of these fibres and their ability to penetrate living tissue; and thirdly on their chemistry, not only considering their resistance to decomposition, but the way in which they may react with or adsorb other compounds. This paper compares the physical and chemical properties of asbestos fibres insofar as these may influence biological activity and attempts to underline those contrasting features which may relate to the degrees of activity of the major types of asbestos.