You searched for: “glauconite
A greenish mineral of the mica group, a hydrous silicate of potassium, iron, aluminum, or magnesium, found in greensand and used as a fertilizer and water softener.

Greensand is a variety of sandstone, usually imperfectly consolidated, consisting largely of glauconite, a silicate of iron and potash of a green color, mixed with sand and a trace of phosphate of lime.

This entry is located in the following unit: glauc-, glauco- + (page 1)