A joint to connect a tubular ceramic element to a tubesheet. The joint has an internal seal housing to retain the tubular ceramic element and an external seal housing connected to the tubesheet to retain the internal seal housing. A ceramic-to-metal seal is located within the internal seal housing and a metal-to-metal seal is located between the internal seal housing and an external seal housing. The external seal housing is connected to the tubesheet. The internal seal housing is assembled in sections to allow assembly of the ceramic-to-metal seal to be assembled and tested prior to joining the tubular ceramic element to the tubesheet. After perfection of such seal, the internal seal housing and tubular ceramic element is inserted into the external seal housing and sealed within the external seal housing by the metal-to-metal seal.