Alteration of tremolite to talc in the dolomite marbles of Yellandu Warangal District (Hyderabad, DN.)

Summary

• 1. Specimens of tremolite from the dolomite marbles of Yellandu showed variations in composition indicating that they have undergone alteration.

• 2. The end-product of alteration was identified to be talc.

• 3. Six different specimens in varying stages of alteration were examined and they revealed a gradual change in specific gravity and chemical composition.

• 4. A definite intermediate stage of alteration was confirmed by examination of some specimens.

• 5. It was established by chemical analysis that during the progress of alteration the following changes take place: (a) almost all the calcium is lost, (b) water of constitution and alumina accumulate and (c) ferrous iron gets fully oxidised.

• 6. It is suggested that meteoric solutions and atmospheric action were mainly responsible for the alteration of tremolite to talc.

• 7. The gains and losses of the various constituents when 100 c.c. of tremolite undergo alteration to an equal volume of talc can be calculated because no change in volume occurs during the alteration of the mineral. The results of such are tabulated in this paper.