According to the most popular models, which are consistent with spectroscopic measurements, the crystal ions in the vertex positions are the first to dissolve. Those on the corners do not react as easily with water molecules and those on the faces have almost zero probability of reacting. However, whenever an ion is removed, new vertices are created.

In this Demonstration, you can change the probability of the site where the next dissolution occurs. The crystal is idealized as a cube in which the anions are shown in red and cations in blue. The "vertex odds" and "corner odds" controls vary the probability of a dissolution at one such site. The bar chart on the left shows the resulting distribution of probability.