Abstract: A heat and vibration resistant seal construction for a valve assembly having a core member constructed of a dense, resilient material which retains its spring-like properties at elevated service temperatures. The core is surrounded by an intermediate wrap member of braided, ceramic fiber forming a co-extensive cover for the core member. Lastly, an outer wrap member constructed of braided wire metal mesh is provided around the intermediate wrap member. In a "tadpole" type seal embodiment, the intermediate wrap and outer wrap members include outwardly extending tail sections to provide means for attachment to the periphery of a valve housing or the like.