Turkish Journal of Physics
Measurements of microhardness anisotropy by Knoop diamond indentations on the prismatic (100) planes of epidote crystals, point group 2/m and space group P21/m, show that microhardness is determined by crystallographic slip on the (100) systems. Microhardness anisotropy is explained in terms of the effective resolved shear stress distribution in these slip systems.
DIN, SALAH-UD; AHMAD, MUNNAWAR; and CHISHTI, SHAHZAD (2001) "Study of Slip Systems in Epidote Single Crystal," Turkish Journal of Physics: Vol. 25: No. 3, Article 7. Available at: https://journals.tubitak.gov.tr/physics/vol25/iss3/7