sodium silicate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various water-soluble silicate glass compounds used as a preservative for eggs, in plaster and cement, and in various purification and refining processes.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a viscous glass consisting of sodium silicate in solution; used as a cement or as a protective coating and to preserve eggs