  Dating from experiments more than 20 years ago, it has been realized that the
crystallization of hard colloidal particles in the vicinity of dynamical arrest
has several anomalies, that render the conventional nucleation and growth model
inappropriate. Subsequently, key researchers have shown the influence of
gravity. Here we show that a simple lattice model can capture most of the
phenomena associated with such systems. In particular, the model reproduces not
only characteristic signatures of glass-forming systems, but also the interplay
between quasi arrested dynamics and crystal nucleation.
