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
Dravo Gravel Site Dravo. The inhabitants' technology prompted their classification as a people of the middle of the Late Archaic Period. In 1978, the Dravo site was listed on the National Register of Historic Places, qualifying because of its archaeological significance. Dravo Gravel Site The Dravo Gravel Site (33HA377) is an archaeological site located above the Great Miami River in Miami Township, Hamilton County, Ohio, United States. Discovered in the middle of a gravel pit, the site is a leading example of the local manifestation of the Archaic period. The site lies atop a Miami River terrace outside the village of Cleves, occupying