Dissolution process and rate in feldspar: Effects of crystallographic orientation.

Abstract

A single-crystal of labradorite with one crystallographic face was hydrothermally treated in acid solution at 90, 120 and 150 degrees C. The dissolution rate on (100) was the largest among three orientations, and that on (010) and (001) were almost the same. Small etch pits were arranged along two directions on (100) under SEM observations, and on (010) and (001) along the cleavage. The dissolution rate on the plane normal to cleavage is faster than that on the plane parallel to the cleavage, indicating that the microtextures play a more important role than the structural characteristics in dissolution of labradorite.