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
Gravel Run (Black Creek) by acid mine drainage in the early 1900s. The acid mine drainage came from mines in and near the city of Hazleton. Gravel Run is entirely within the United States Geological Survey quadrangle of Hazleton. It drains a portion of the northwestern part of the city of Hazleton. It drains the older part of the city as well as the Green Ridge Territory. Gravel Run is one of eleven officially named streams in the watershed of Nescopeck Creek that has not been assessed by the Pennsylvania Fish and Boat Commission. Gravel Run was entered into the Geographic Names Information System