HOW DO I MEND BROKEN POTTERY LAMP BASE?

THE LAMP BASE IS BROKEN IN SEVERAL PIECES. tHE MATERIAL UNDER THE COLORED GLAZE IS WHITE, SHALE-LIKE AND COMES APART EASILY. sHOULD I USE A GLUE OR A BONDING MATERIAL OF SOME SORT. IT IS ONE OF A MATCHING PAIR OF DRESSING TABLE LAMPS FROM THE 20S AND HAS SENTIMENTAL VALUE FOR ME. ANY HELP YOU CAN GIVE WOULD BE VERY MUCH APPRECIATED.