Studies on South Indian radioactive minerals II. Allanite from Madura

Abstract

Allanite, a cerium-bearing epidote occurring in the pegmatites of Kavarkattumalai, Madura District, has been studied in detail. The investigations comprise the determination of physical and optical characters, chemical composition, mineral formula, and autoradiographic studies. Attempts have been made from a study of the data on metamict and non-metamict allanites to formulate the changes that allanite undergoes when it becomes metamict. Evidence has been collected to show that the allanite from Madura had become metamict and is hence of dubious value as an age index.