There is provided a catalyst carrier comprising a refractory inorganic material having a sodium solubilization rate no greater than 5 ppmw/5 minutes. There is further a catalyst comprising a refractory inorganic material carrier having a sodium solubilization rate no greater than 5 ppmw/5 minutes; and one or more catalytically reactive metals deposited on said carrier. There is also provided a catalyst suitable for the vapor phase production of alkylene oxide from olefins and oxygen comprising an alumina-based carrier having a sodium solubilization rate no greater than 5 ppmw/5 minutes; and catalytically reactive silver deposited on said carrier.