[Asbestos minerals: their recognition and determination]

Fibers of amphibolic and serpentinic asbestos may be optically distinguished by the method proposed by the AA. The method is based on the observation at the microscope in reflected fluorescence of fibers of asbestos previously treated with a fluorochrome colouring agent; it can be applied for the individual counting of fibers on the filters used for checking the environmental air and has already been applied with good results in asbestic cement factories.