Grain size Grain size Grain size (or particle size) is the diameter of individual grains of sediment, or the lithified particles in clastic rocks. The term may also be applied to other granular materials. This is different from the crystallite size, which refers to the size of a single crystal inside a particle or grain. A single grain can be composed of several crystals. Granular material can range from very small colloidal particles, through clay, silt, sand, gravel, and cobbles, to boulders. Size ranges define limits of classes that are given names in the Wentworth scale (or Udden–Wentworth scale) used in the
Paxton (soil) Paxton (soil) The Paxton soil series was established in Worcester County, Massachusetts in 1922, and is named for the town of Paxton where it was first described and mapped. Coarse-loamy, mixed, active, mesic Oxyaquic Dystrudepts. Paxton soils are in the Inceptisol soil order of soil taxonomy. The term "coarse-loamy" indicates that the soil has less than 18% clay and at least 15% or more particles that are fine sand or coarser. The term "mixed" indicates no single mineral is over 40 percent. The term "active" represents a ratio of the cation-exchange capacity to clay of the pedon. The term "mesic"