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
Mike Gravel Washington, D.C. Short on campaign cash, he took public transportation to get to his announcement. (Gravel called for public financing of elections.) Other principal Gravel positions were the FairTax, withdrawal of U.S. troops from Iraq within 120 days, a single payer national health care system, and term limits. In particular, he had opposed the Iraq War from the beginning, and in 2006 Gravel said that U.S. troops in Iraq, as in Vietnam, had "died in vain". He also favored a regional peace initiative, as well as reparation payments for Iraqis. Gravel also called for a "U.S. corporate withdrawal from Iraq",