ASBESTOS is the generic name for those silicate minerals which cleave naturally into fibres, the three important species being chrysotile (white asbestos), crocidolite (blue asbestos) and amosite. This unique mineral structure lends itself better to measurements of tensile strength than do the more common minerals with isotropic or platy structures, which are extremely difficult to prepare in the form of adequate tensile specimens, although measurements on mica have been reported1.