Phases_wbg.png
Another representation of the density of the various states.1 In the solid regime, increasing pressure doesn't further compress the matter — it simply enables the closest packed arrangement even at increasing temperatures.
References
1. Weill, F. et al. (1999): Supercritical fluid processing: a new route for materials synthesis. Journal of Materials Chemistry, 9 (1): 67-75 ⇧