![Coarse Silica Sand](http://psh.ca/cdn/shop/products/MS204_{width}x.jpg?v=1648738587)
Quartz sand. A refractory used on kiln shelves to ease shrinkage movement of large pieces or, in limited amounts, as a grog in sculpture clay bodies.
For more information on silica sand, see the Digitalfire.com Reference Library of ceramic materials.