diatomaceous earth; diatomite; siliceous marl; kieselguhr
silicon dioxide (SiO2); silica
sodium silicate (Na2SiO3)
pneumonoultramicroscopicsilicovolcanoconiosis; pneumonoultramicroscopicsilicovolcanokoniosis
silicon tetrachloride (SiCl4)
siliceous sponge (any sponge other than those of class Calcarea)
red and white-speckled silica