Abstract: A foaming sealant or cement for use in securely joining shaped thermally crystallizable glass bodies and shaped glass-ceramic bodies previously formed by thermal in situ crystallization of thermally crystallizable shaped glass bodies wherein the sealant consists essentially of from (1) about 80-99% by weight of a glass frit having SiO.sub.2, Al.sub.2 O.sub.3, Li.sub.2 O and usually CeO.sub.2 as the essential ingredients, (2) about 2-15% by weight of ZnO powder when the mole percent of the CeO.sub.2 in the glass frit is below about 2, and (3) an amount by weight of SiC powder sufficient to be decomposed during the firing of the sealant to form gas which, in turn, foams the sealant. Such sealant can be fired and bonded to shaped glass-ceramic bodies at temperatures below 2192.degree. and as low as 2150.degree. F and even lower. The sealant is dimensionally stable when subjected to high temperatures over long periods of time and has an average coefficient of thermal expansion of from about -15 .times. 10.sup.-.