meerschaum

n. [ G., lit., sea foam; meer sea + schaum foam; but it perh. is a corruption of the Tartaric name myrsen. Cf. Mere a lake, and Scum. ] 1. (Min.) A fine white claylike mineral, soft, and light enough when in dry masses to float in water. It is a hydrous silicate of magnesia, and is obtained chiefly in Asia Minor. It is manufacturd into tobacco pipes, cigar holders, etc. Also called sepiolite. [ 1913 Webster ]

2. A tobacco pipe made of this mineral; a meerschaum pipe. [ 1913 Webster ]