Vermiculite in its macroscopic form occurs in the Archaean supracrustal rocks exposed towards east of Sargur supracrustal complex in Karnataka state. The present study forms the first detailed work on the occurrence of vermiculite associated with the ultramafic rocks in the Agasthyapura, which lies in the long. 76° 50’ 658” and lat. 12° 15’ 976”. Petrography, X-ray diffraction, FTIR, DTA&TGA, SEM, fluid inclusion and electron probe analyses are presented in this contribution study. The probable origin of vermiculite from biotite through hydrobiotite is discussed., Kikkeri N. Prakash Narasimha, Honnaiah Ramalingaiah, Karel Melka, K. Krishnaveni, Pinnelli S. R. Prasad, Chikkamadaiah Krishnaiah, Katihalli S. Jayappa and Atni V. Ganesha., and Obsahuje bibliografické odkazy