Source : Webster's Revised Unabridged Dictionary (1913)

Glauconite \Glau"co*nite\, n. [Cf. F. glauconite, glauconie, fr.
   L. glaucus. See {Glaucous}.] (Min.)
   The green mineral characteristic of the greensand of the
   chalk and other formations. It is a hydrous silicate of iron
   and potash. See {Greensand}.

Source : WordNet®

glauconite
     n : a green mineral consisting of hydrated silicate of potassium
         or iron or magnesium or aluminum; found in greensand