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
Granular pugolovka Granular pugolovka The granular pugolovka ("Benthophilus granulosus") is a species of gobiid fish widespread in the Caspian Sea. It is a small fish, with a length up to TL. It was listed as Least Concern by the IUCN in 2008: there are no known major threats. Granular pugolovkas are very abundant in their habitat due to their size and lack of natural predators. The common name 'pugolovka' is a Ukrainian word for tadpole. "Benthophilus granulosus" has a flat head with a flat barbel on the chin that is often described as being leathery. The body colors depend on the habitat