Assessment of the potential hazard represented by natural raw materials containing mineral fibres-The case of the feldspar from Orani, Sardinia (Italy).

•A procedure to unambiguously identify the nature of the asbestos minerals in a natural feldspar raw materials was applied.•The investigated feldspar raw material from Orani (Sardinia) contains tremolite asbestos and represents a potential hazard.•Electron probe microanalysis permitted to rule out the presence of fibrous amphiboles other than tremolite.•Most of the tremolite asbestos fibres present in the raw material from Orani (Sardinia) are respirable.