| Investigation by X-ray diffraction and infra-red carried
out on samples of massive sillimanite and quartz-free
quartz-sillimanite schist from Sonapahar area as such, as
well as on tiny single crystals, picked up therefrom, under
a microscope indicated the presence of mullite beside four,
forms of sillimanite. Rutile and biotite were also found to
occur in the schist. Densities of three forms of sillimanite
were found to be 3.22, 3.19, 3.26 gmfcc but density of
mullite was 3.06 gmfcc. |
