any of various greenish, clayey materials; spec. †(a) crude borax (obsolete); (b) the pigment terre verte; (c) Mineralogy the mineral glauconite.

Hydrous silicate of iron, potassium, and other bases, commonly called green earth.

Geology. Also with capital initial. Sand or imperfectly consolidated sandstone of a greenish colour, often resulting from the presence of…