Soil mechanics weathering of feldspar, which is the most common mineral present in igneous rock. The most common mineral constituent of silt and sand is quartz, also called silica, which has the chemical name silicon dioxide. The reason that feldspar is most common in rocks but silica is more prevalent in soils is that feldspar is much more soluble than silica. Silt, Sand, and Gravel are basically little pieces of broken rocks. According to the Unified Soil Classification System, silt particle sizes are in the range of 0.002 mm to 0.075 mm and sand particles have sizes in the range of 0.075
Gravel chub May and continuing into June. Adult gravel chubs have been spotted spawning by gathering on gravel bars in soft currents created by a rise in the waterline after hard rains. The gravel chub is considered a threatened species in many areas mostly due to the fact that it has a highly specific, clean habitat need. As of 1988 it was considered endangered in Kansas, under legal protection in Indiana and Wisconsin and considered a special concern in Kentucky, Minnesota and New York. Gravel chubs need constant mild currents with silt free riffles. Agriculture run-off is the biggest threat to this