A CLAY FOAM CHARACTERIZED BY A CLOSED CELL STRUCTURE AND THE ABILITY, IN ITS CALCINED STATE, TO FLOAT IN WATER IS DESCRIBED. THE GAS BUBBLES OF THE FOAM ARE SUBSTANTIALLY COMPLETELY ENCAPSULATED BY WALLS FORMED FROM CLAY PARTICLES. THE FOAM IS PREPARED BY GENERATING A FOAMING GAS IN AN AQUEOUS DISPERSION OF CLAY PARTICLES TO WHICH HAS BEEN ADDED A MINOR AMOUNT OF A FATTY AMINE AS A FOAMING AGENT. A VARIETY OF INORGANIC FILLER MATERIALS CAN BE INCORPORATED INTO THE FOAM IN ORDER TO ALTER OR IMPART NEW PROPERTIES TO THE FOAM. THE FOAM CAN BE CALCINED TO FURTHER ALTER ITS PROPERTIES. THE FOAM HAS MANY USES INCLUDING USE AS A REFRACTORY BRICK.