Chalk produce, and thus widely used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, and is marketed as "dustless chalk". Colored chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often colored), used to draw on sidewalks, streets, and driveways, are primarily made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits. Such bell pits may also mark the sites of ancient flint mines,
Chalk of war, chalk — now usually magnesium carbonate — is applied to the hands and feet to remove perspiration and reduce slipping. Chalk may also be used as a house construction material instead of brick or wattle and daub: quarried chalk was cut into blocks and used as ashlar, or loose chalk was rammed into blocks and laid in mortar. There are still houses standing which have been constructed using chalk as the main building material. Most are pre-Victorian though a few are more recent. Chalk Chalk is a soft, white, porous, sedimentary carbonate rock, a form of limestone composed