controlled pH conditions. It is also used as a type of rock for stone walls in areas where greensand is common. In Roman times in Britain, coarse grits derived from the lower greensand were used to line the inner surface of mortars (grinding bowls) produced in Oxfordshire pottery kilns. Recently, glauconitic greensand has become a popular organic soil amendment. The porous properties of glauconite greensand allows for the absorption of water and minerals, making irrigation and nutrient delivery much more efficient (see soil conditioner). Greensand can be used to absorb excess water in clay-rich soils and to prevent water loss in sandy soils. See also Glauconite References External links Greensand at the Arkansas Geological Survey Glauconite (Greensand) at the Delaware Geological Survey (as a commodity) Sandstone Sedimentary rocks