mendipite

from The Century Dictionary.

• noun A rare oxychlorid of lead, usually occurring in fibrous or columnar radiated masses, also crystallized, of a white color and pearly luster. It is found in the Mendip hills, Somerset, England.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mineralogy An orthorhombic-disphenoidal mineral containing chlorine, lead, and oxygen.