meerschaum

noun

1. a mineral, hydrous magnesium silicate, H4Mg2Si3O10, occurring in white, claylike masses, used for ornamental carvings, for pipe bowls, etc.; sepiolite.
2. a tobacco pipe with a bowl made of this substance.

noun

1. Also called: sepiolite a white, yellowish, or pink compact earthy mineral consisting of hydrated magnesium silicate: used to make tobacco pipes and as a building stone. Formula: Mg 2 Si 3 O 6 (OH) 4
2. a tobacco pipe having a bowl made of this mineral

n.type of soft white clay, 1784; from 1789 as “tobacco pipe with a bowl made of meerschaum clay,” from German Meerschaum, literally “sea-foam,” so called from its frothy appearance; from Old High German mari “sea” (see mere (n.)) + 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.