meerschaum (n.)

type of soft white clay, 1784; from 1789 as "tobacco pipe with a bowl made of baked meerschaum clay," from German Meerschaum, literally "sea-foam," so called from its frothy appearance; from Old High German mari "sea" (see mere (n.1)) + scum "scum" (see skim (v.)). A loan-translation of Latin spuma maris, itself said to be a loan translation of Greek halos akhne, from Persian kaf-i-darya.