mordenite

from The Century Dictionary.

• noun A zeolitic mineral occurring in small hemispherical forms with a fibrous structure, whitish color, and silky luster. it is a hydrous silicate of aluminium, calcium, and sodium, and is found near Morden in Nova Scotia.

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

• noun mineralogy An orthorhombic-pyramidal mineral containing aluminum, calcium, hydrogen, oxygen, potassium, silicon, and sodium.