This work describes the nature of the potentially hazardous fibrous amphibole found in the Orani's feldspar mine (Sardinia, Italy). To identify its nature, a protocol of analysis including morphometric, chemical and crystal-lographic characterizations was applied. Thanks to this approach, it was possible to classify the observed fibres as tremolite after comparing chemical data, SEWTEM observations, FTIR/Raman spectra and X-ray diffraction data with those reported for a standard sample. The unit cell parameters of the investigated tremolite phase are a = 9.82(1) angstrom, b = 18.08(3) angstrom, c = 5.27(1) angstrom, and the angle beta corresponds to 104.4(1)degrees. The mean concentration of asbestos tremolite in the Orani's feldspar is 0.28 wt%. Most of the fibres (0.26 wt%) are respirable 'regulated' fibres, representing a potential hazard. Because the total amount of tremolite in the sample is 0.6 wt%, a large fraction of it has a crystal habit other than fibrous-asbestifonn or acicular. The obtained results allowed us to suggest possible solutions for a safe exploitation and mineral processing of the Orani's mine. The procedure proposed herein may be a general tool suitable to identify the mineralogical nature of fibrous minerals in raw materials and assess if they may represent a potential health/environmental hazard.