VANSIL CS-1 Wollastonite, a natural calcium silicate mineral, is unique among soil amendments as a source of silicon and carbon-neutral calcium. VANSIL CS-1 wollastonite is sourced from a Vanderbilt Minerals deposit and processing facility in northern New York state. It is the only OMRI certified wollastonite mined and milled in the United States. More information on VANSIL CS-1.