(written from a Production point of view)
In a deleted scene from the Star Trek: Enterprise episode "Fallen Hero", warm Eluvian mud was established as having been used to fill a Risan isolation chamber. This had been used for meditation by T'Pol on a previous visit to Risa that she undertook. In the scene, she mentioned the mud when she recalled the occasion while speaking with Ensign Travis Mayweather, Lieutenant Malcolm Reed and Ensign Hoshi Sato. In the final draft script of "Fallen Hero", the name of this type of mud is phonetically notated to be pronounced "eh-LOO-vee-an".