This is the structure the soil has under the microscope. It is related with the size, shape and arrangement of the primary particles and the voids in aggregate and non-aggregate materials and the size, shape and arrangement of any aggregate present.
Microstructures of sand grains
Single grains. Almost entirely formed of sand grains, without, or with very little,
fine material between the grains. Loose grains, or slightly touching.
Bridged grains. Sand grains joined by bridges of fine material.
Pellicular grains. Sand grains covered with a pellicle of fine material.
Intergrain micro-aggregates. There are fine material micro-aggregates between the sand grains.
Intergrain vesicles. With vesicles between the sand grains.
Intergrain channels. With channels between the sand grains.
Compact grains. With sand grains very close together, leading to a very compact structure.
Neither aggregate nor sandy microstructures