Brownstone and sandstone buildings disintegrate readily - the surface may rub off, significant segments of rock may divide and lost,,, or the facade can become blistered or broken. These issues dealt with in a fresh eight - page pamphlet," The Care and Repair" prepared by the New York Landmarks Conservancy. Brownstone is the most popular name for a variety of pink, reddish, purple and brown sandstones extensively applied before the early 20th century in the New York area in the Civil War. In the 19th century, it had been cheaply got from the Connecticut River Valley as well as quarries. Fort Greene in the side streets of Manhattan and Brooklyn, many brownstone row houses still sand. There may be" tens of thousands" in town, in accordance with Laurie Beckerman, executive director. Sandstone is a layered, sedimentary stone, frequently formed in stream beds. If the water gets into the pores, it may freeze and expand and fracture the surface of the building. Or in the event the water is in the type chemical it can cause disintegration. Recognizing these as well as other issues for the owners a study was begun by the Conservancy in 1979 on the best way to fix them.