Graystar LLC GNPGraystar Specialty Materials is one of the premier raw material suppliers worldwide for the ceramic and abrasive markets. Graystar LLC is one of the largest suppliers of abrasive grains and ceramic materials in the world. With office and warehouse facilities in both Bluffton, South Carolina and Niagara Falls, New York the company has the ability to provide materials to a diverse range of geographic markets throughout North America and the world.