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 Learn October 2017, Blackboard partnered with OpenEd to integrate OER with Learning Management Systems. Blackboard Learn provides users with a platform for communication and sharing content. Blackboard Inc has had several legal issues, including faulty patent rights claims. In addition, a number of educational institutions, teachers, and students have expressed concerns about the reliability of Blackboard. McMaster University in Hamilton, Ontario, Canada, has replaced their Blackboard system after multiple problems during one year of use. Citing numerous glitches and high costs, many universities are turning to the cheaper, open source alternative Moodle, including Montana State University, Vassar College, California State University,