Grains not bounded by crystal faces. Crystalline particles are also characterized by a particular habit. Roundness is defined as description of the relative sharpness of the particle corners. Secondary corners are numerous and sharp. Stronly developed faces with somewhat rounded edges and corners.
Secondary corners are numerous.
Secondary corners are greatly subdued and few. No secondary corners. An important property of particles, aggregates, voids and some pedofeatures is their surface character. Roughness can arise from a number of processess, e.g. weathering of mineral particles, mastication of plant fragments by soil animals, projection of coarse and fine mineral particles along void walls and crystallization onvoid walls. Processes that give rise to smoothness include translocation of particles, some forms of chemical precipitation, depostion of clay at pore and aggregate edges and movement of soil fauna through soil material.