Do minerals in rocks ever pose a health hazard?
Sometimes. For example serpentine is a common rock in California where it occurs abundantly in coastal mountain ranges; and there is a commercially important belt of serpentine in Quebec, Canada. Serpentine (magnesium silicate) is a metamorphic rock which contains soft, silky fibres of chrysotile asbestos. Asbestos fibres can withstand fire and insulate against heat and they are used in automobile brake linings, heat resistant tapes, cloth and insulating materials. A health hazard can occur during the asbestos extraction process and aslo when the serpentine rock is crushed for use in road construction. Asbestos fibres in the air are breathed into the lungs. This is a problem because asbestos fibres can work their way into tissues and cells. This can cause asbestosis which is a chronic lung disease. Certain types of asbestos are carcinogenic in that they cause lung and other cancers.
