A neologism for “coal” coined by Helge Fauskanger for his Neo-Quenya New Testament (NQNT) derived from the root ᴹ√YUL “smoulder” from The Etymologies from 1930s, probably based on a primitive s-prefix: *s-yul-mā. In later writings Tolkien used the root √YUL for “drink”, but I recommend transferring the 1930s meaning to a Neo-Root ᴺ√YOL/YUL “smoulder” and thus think this neologism is salvageable.