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
Rock Sand to his best position of second on the list of leading sires. On his four-year-old debut, Rock Sand ran against Sceptre again in June over the Derby course and distance in the Coronation Cup, a race which also featured the first meeting between Rock Sand and his contemporary Zinfandel, a colt whose engagements in the previous year's classics had been rendered void by the death of his owner Colonel Harry McCalmont. Zinfandel won easily from Sceptre, with Rock Sand third. Rock Sand avoided Zinfandel for the remainder of the season and was unbeaten in his remaining five races. He won