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.