Epsomas Organic Traditions Greensand is the highest quality, all natural, non-burning, purest Greensand obtainable. Greensand is mined from natural deposits of glauconite. These deposits are of marine origin and are composed primarily of iron-potassium silicate, wich gives it its bluisgreen color. Potassium is an essential nutrient needed by all plant life. Other properties of greensand are its ability to loosen clay soils, bind sandy soils, and increase the waterholding capacity of all soils. It is an exceptional soil conditioner for flower beds, gardens, and lawns.