Granular material physics of granular matter and whose book "The Physics of Blown Sand and Desert Dunes" remains an important reference to this day. According to material scientist Patrick Richard, "Granular materials are ubiquitous in nature and are the second-most manipulated material in industry (the first one is water)". In some sense, granular materials do not constitute a single phase of matter but have characteristics reminiscent of solids, liquids, or gases depending on the average energy per grain. However, in each of these states granular materials also exhibit properties which are unique. Granular materials also exhibit a wide range of pattern forming
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