 it has been recognized since at least as early as the mid-1500s that inhaled minerals ( i.e. , inorganic particles ) can pose a risk . 
 extensive research has focused on the biological mechanisms responsible for asbestos- and silica - induced diseases , but much less attention has been paid to the mineralogical properties and geochemical mechanisms that might influence a mineral 's biological activity . 
 several important mineralogical characteristics control a mineral 's reactivity in geochemical reactions and are likely to determine its biological reactivity . 
 in addition to the traditionally considered variables of particle size and shape , mineralogical characteristics such as dissolution behavior , ion exchange , sorptive properties , and the nature of the mineral surface ( e.g. , surface reactivity ) play important roles in determining the toxicity and carcinogenicity of a particle . ultimately , a mineral 's species ( which provides direct information on a mineral 's structure and composition ) is probably one of the most significant yet most neglected factors that must be considered in studies of toxicity and carcinogenicity.imagesfigure 4 . 
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