1. n. [Geology]
The arrangement in space of uniform spheres (atoms and molecules in mineral crystals, or grains in clastic sedimentary rocks) that results in a cubic material structure. Cubic packing is mechanically unstable, but it is the most porous packing arrangement, with about 47% porosity in the ideal situation. Most sediments are not uniform spheres of the same size, nor can they be arranged in a cubic structure naturally, so most sediments have much less than 47% porosity.
See: clastic sediment, porosity, rhombohedral packing, sediment, sorting