In-situ atomic force microscope imaging of calcite etch pit morphology changes in undersaturated and 1-hydroxyethylidene-1,1-diphosphonic acid poisoned solutions

Morphology changes in etch pits formed on the (1014) cleavage plane of calcite were induced by varying the ratio of [Ca2+] to [CO32-] in the bulk solution as well as through the addition of the crystal poison 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP). Three distinct morphologies were noted: symmetric rhombic, asymmetric rhombic, and triangular with a rough curved hypotenuse. The latter represents a transient morphology which is only observed during the actual dissolution process, while the former morphologies persist after dissolution is halted.