'Glauconite' definitions:

Definition of 'glauconite'

(from WordNet)
noun
A green mineral consisting of hydrated silicate of potassium or iron or magnesium or aluminum; found in greensand

Definition of 'Glauconite'

From: GCIDE
  • 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. [1913 Webster]