Abstract: A two part castable ceramic cement having low density, good thermal shock resistance, good temperature resistance and extended storage life. The first and second parts are mixed together prior to use. The first part is a slurry of solids in water. The solids comprise 0 to 10 weight percent organic fibers, about 35 to about 80 weight percent ceramic organic fibers, about 5 to about 15 weight percent colloidal silica and about 3 to about 10 weight percent organic adhesive. The second part is essentially dry and comprises from about 50 to about 100 weight percent calcium aluminate.The invention further includes a method for forming the cement by mixing the two parts and includes the cast cement resulting from casting and drying the mixed first and second parts.