The classification of soil structural forms is based largely on shape.
# Spheroidal structure: sphere-like or rounded in shape. All the axes are approximately of the same dimensions, with curved and irregular faces. These are found commonly in cultivated fields.
## Crumb structure: small and are like crumbs of bread due to them being porous
## Granular structure: less porous than crumb structure aggregates  and are more durable than crumb structure aggregates
# Plate-like structure: mainly horizontally aligned along plant based areas, with thin units being laminar and the thick units of the aggregates are classified as platy. Platy structures are usually found in the surface and sometimes in the lower sub-soils.
# Block-like structure: particles that are arranged around a central point are enclosed by surfaces that may be either flat or somewhat rounded. These types are generally found in subsoil.
## Sub angular blocky: corners are more rounded than the angular blocky aggregates
#  Prism-like structure: particles that are longer than they are wide, with the vertical axis being greater than the horizontal axis. They are commonly found in subsoil horizon of arid and semi-arid region soils.
## Prismatic: more angular and hexagonal at the top of the aggregate
## Columnar: particles that are rounded at the top of the aggregate