A FURNACE TANK FOR USE IN THE PRODUCTION OR TREATMENT OF GLASS FLOATING ON A BATH OF MOLTEN MATERIAL HAS AT LEAST ONE WALL FORMED OF A REFRACTORY ELEMENT. THE ELEMENT COMPRISES A REFRACTORY BODY HAVING A REFRACTORY COATING DIFFERENT IN COMPOSITION FROM THE BODY ADHERING TO AT LEAST A PORTION OF THAT FACE WHICH IS DIRECTED TOWARD THE INTERIOR OF THE TANK. THE REFRACTORY COATING IS PREFERABLY APPLIED TO A FACE OF THE BODY IN THE FLOWABLE STATE AND SETS IN SITU.