Blackboard ‘chalk’ are produced especially for use with blackboards in white and also in various colours. White chalk sticks are made mainly from calcium carbonate derived from mineral chalk rock or limestone, while colored or pastel chalks are made from calcium sulfate in its dihydrate form, CaSO·2HO, derived from gypsum. Chalk sticks containing calcium carbonate typically contain 40–60% of CaCO (calcite). As compared to whiteboards, blackboards still have a variety of advantages: On the other hand, chalk produces dust, the amount depending on the quality of chalk used. Some people find this uncomfortable or may be allergic to it, and according
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