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
Emery, Utah identify archaeological sites as Fremont, is not very different from that made by other Southwestern groups, nor are its vessel forms and designs distinct. What distinguishes Fremont pottery from other ceramic types is the material from which it is constructed. Variations in temper, the granular rock or sand added to wet clay to insure even drying and to prevent cracking, have been used to identify five major Fremont ceramic types. They include Snake Valley gray in the southwestern part of the Fremont region, Sevier gray in the central area, Great Salt Lake gray in the northwestern area, and Uinta and