Calcium sulfate an unusual property: when mixed with water at normal (ambient) temperatures, it quickly reverts chemically to the preferred dihydrate form, while physically "setting" to form a rigid and relatively strong gypsum crystal lattice: This reaction is exothermic and is responsible for the ease with which gypsum can be cast into various shapes including sheets (for drywall), sticks (for blackboard chalk), and molds (to immobilize broken bones, or for metal casting). Mixed with polymers, it has been used as a bone repair cement. Small amounts of calcined gypsum are added to earth to create strong structures directly from cast earth, an
Chalk carving art. In India Artist Ramita Bhaduri is the pioneer in Chalk Sculpture. For more than two decades she has used chalk to create a variety of forms and compositions. There are two types of chalk carvings. A carved object or relief consisting of one piece of chalk. A carved object or relief using two or more individual pieces of chalk. Chalk carving Chalk carving is the practice and shaping of chalk via carving . This article covers some methods, types of chalk, tools used and the benefits (and ramifications) of this material. The benefits of this material are also its