Compaction of frictional octahedra

We perform experiments with frictional polypropylene octahedra to study the packing properties. Starting with the loose packing, compaction of octahedra is done by two types of forcing -- a) tapping and b) shearing. The compaction gives rise to crystallization of octahedra due to heterogenous nucleation from the walls. We obtain the X-ray tomograms of the packing configurations as a function of packing fraction. From the contact geometries we obtain results for the packings such as - pair correlation function, distance to isostaticity, and spatial {\&} angular correlation functions. We contrast these results with a similar study on the simplest platonic solid, the tetrahedron\footnote{Jammed frictional tetrahedra are hyperstatic, M. Neudecker, S. Ulrich, S. Herminghaus, M. Schr\"{o}ter. (arXiv:1202.6272v2)} and the sphere.