Chalk It is formed in the sea by sub-microscopic plankton, which fall to the sea floor and are then consolidated and compressed during diagenesis into chalk rock. Most people first encounter the word "chalk" in school where it refers to blackboard chalk, which was originally made of mineral chalk, since it readily crumbles and leaves particles that stick loosely to rough surfaces, allowing it to make writing that can be readily erased. Blackboard chalk manufacture now may utilize mineral chalk, other mineral sources of calcium carbonate, or the mineral gypsum (calcium sulfate). While gypsum-based blackboard chalk is the lowest cost to
Blackboard Inc. Engage. In March 2012, Blackboard acquired Moodlerooms Inc. and NetSpot of Adelaide, Australia, which then became the basis of Blackboard's Open Source Services division. From January 2014 to April 2015, Blackboard acquired nine companies, including: MyEdu, an Austin-based online education company; Perceptis, a provider of help desk and administrative services; CardSmith, a company that offered cards for student ID and on-campus payments; Requestec, a provider of technology for VoIP, video conferencing and instant messaging; and Schoolwires, a company that specialized in building school websites. In August 2015, Blackboard acquired Colombia-based Nivel7, possibly the largest Moodle services provider in Latin America.