[glaw-kuh-nahyt] 
| a greenish micaceous mineral consisting essentially of a hydrous silicate of potassium, aluminum, and iron and occurring in greensand, clays, etc. |
| glau·co·nite (glô'kə-nīt') n. A greenish mineral of the mica group, a hydrous silicate of potassium, iron, aluminum, or magnesium, (K,Na)(Al,Fe,Mg)2(Al,Si)4O10(OH)2, found in greensand and used as a fertilizer and water softener. [German Glaukonit : Greek glaukon, neuter of glaukos, gray + -ite1.] glau'co·nit'ic (-nĭt'ĭk) adj. |
glauconite
greenish ferric-iron silicate mineral with micaceous structure [(K, Na)(Fe3+,Al, Mg)2(Si, Al)4O10(OmicronH)2], characteristically formed on submarine elevations ranging in depth from 30 to 1,000 metres (100 to 3,300 feet) below sea level. Glauconite is abundant only in sea-floor areas that are isolated from large supplies of land-derived sediment.
Learn more about glauconite with a free trial on Britannica.com.
kəˌnaɪt