Meerschaum, or Sepiolite, a soft whitish, yellowish, or grayish claylike mineral. Some meerschaum is so porous that it floats in water. Its main use is in the making of tobacco pipes (called meerschaums) and cigar and cigarette holders. A new meerschaum pipe is usually whitish or grayish, but will gradually turn to a rich brown if smoked properly. Meerschaums are expensive and fragile, and have been largely replaced by briar pipes.

The mineral is composed of silicon, magnesium, oxygen, and water. In its natural state, meerschaum sometimes resembles a foamy lather. (Its name is the German word for sea foam.) The chief deposits of meerschaum are in Turkey.

Meerschaum is a hydrous magnesium silicate. Chemical formula: Mg3Si4O114H2O. Specific gravity: 2.0. Hardness: 2.0-2.S.