U.S. Silica Holdings, Inc. is a domestic producer of commercial silica, a specialized mineral that is an input into a range of end markets. The Company operates in two segments: Oil & Gas Proppants, and Industrial & Specialty Products. In the Oil & Gas Proppants segment, it serves the oil and gas recovery market providing fracturing sand, or frac sand, which is pumped down oil and natural gas wells to prop open rock fissures and manage the flow rate of natural gas and oil from the wells. As of December 31, 2016, the Industrial & Specialty Products segment consisted of over 215 products and materials, which are used in a range of industries, including container glass, fiberglass, specialty glass, flat glass, building products, fillers and extenders, foundry products, chemicals, recreation products and filtration products. It produces and sells a range of commercial silica products, including whole grain and ground products, as well as other industrial mineral products.