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
Blackboard Inc. to the non-profit IMS Global Learning Consortium developing a prototype for online learning and thinking through online learning standardization. Chasen and Pittinsky started Blackboard after leaving KPMG Consulting where they both had worked as part of the company's higher education practice. In 1998, after Cane met Chasen at a conference on adaptive learning, Gilfus and Cane decided to merge CourseInfo LLC. with Chasen and Pittinky's Blackboard LLC. company in order to raise money and scale the business. The combined company became a corporation known as Blackboard Inc. They renamed the CourseInfo platform built by the Cornell team to Blackboard's CourseInfo;