The Collaborative International Dictionary of English v.0.48:
Kiefekil \Kie"fe*kil\, n. [Per. keff foam, scum + gil clay, mud.] (Min.) A species of clay; meerschaum. [Also written keffekil.] [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Keffe-kil \Kef"fe-kil\, n. (Min.) See Kiefekil. [1913 Webster]