Naturally occurring in marine sedimentary deposits, Down To Earth™ Greensand is composed primarily of the blue-green siliceous mineral glauconite. Traditionally used to loosen heavy clay soil or to hold together loose sandy soils, DTE™ Greensand is able to absorb up to one-third its weight in water to improve the moisture holding capacity of garden soils and potting mixes. DTE™ Greensand is highly recommended for vegetables, fruits, herbs, lawns, ornamentals and all types of trees and shrubs.