Practical stress analysis using piedmontite microboudinage structures

This paper proposes a practical method for inferring the relative magnitude of differential stress during plastic deformation using piedmontite microboundinage structures in quartz schists. The method only deals with the proportion ( p) of broken grains of piedmontite, and demonstrates that an increase in p value is roughly indicative of a larger differential stress. If the number of measured grains exceeds 100, the confidence interval of the p value becomes less than 0.1, providing a first approximation of the relative magnitude of the differential stress.