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
Gordon Chalk Mansfield swore in Chalk as Premier on 1 August, pending the Country Party electing a new leader. They chose Joh Bjelke-Petersen, who succeeded Chalk after a week in office. Chalk continued as Treasurer and Leader of the Liberal Party until his resignation from parliament in 1976. In the Queen's Birthday Honours of June 1971, he was made a Knight Commander of the Order of the British Empire (KBE). Upon his death in 1991 Chalk was accorded a State funeral which was held at Albert Street Uniting Church and he was later cremated. Gordon Chalk Sir Gordon William Wesley Chalk, (16