Meerschaum. See Meerschaum.

a white clayey mineral

Sepiolite is a clay mineral, a complex magnesium silicate, a typical formula for which is Mg4Si6O15(OH)2 • 6H2O. It can be present in fibrous, fine-particulate, and solid forms. It is used in oil drilling and also in a solid form known as Meerschaum for carving.