In the present work, volcaniclastic rock samples belonging to Fara and Saiq Formations, outcropping in Jebel Akhdar mountains, Oman, are studied with Raman spectroscopy and Electron Microprobe EMP aiming: of i the identification of different naturally occurring TiO 2 polymorphs, ii the evaluation of their trace element contents in relation with hydrothermal alteration features, and iii the analysis of the mineral reactive pathways behind the observed textural relationships. ...