>99% quartz sand. A fine, rounded-grain refractory used on kiln shelves to ease shrinkage movement of large pieces or, in limited amounts, as a grog in sculpture clay bodies.
Grain size: 0.1% retained on 40 mesh; 7.7% on 50m; 34.3% on 70m; 34.6% on 100m; 17.6% on 140m; 5.1% on 200m; 0.5% on 270m.
For more information on silica sand, see the Digitalfire.com Reference Library of ceramic materials.