Distribution of Industrial Minerals in Sardinia (Italy): Clinoptilolite Bearing Rocks of the Logudoro Region

Volcaniclastic products of Northern Sardinia (Italy) turned out to be affected by diffuse zeolitisation processes. About 130 samples, representative of the identified formations (pyroclastic flows and epiclastic deposits), were collected in order to evaluate the distribution of zeolitic phases. Clinoptilolite was the most widespread zeolite, whereas mordenite and chabazite rarely occured. A quantitative evaluation performed by the Reference Intensity Ratio (RIR) and Rietveld methods indicated that about 30% and 44% of samples from pyroclastic flows and epiclastic deposits, respectively, have a zeolite content higher than 50%.