Knowledge Crystallisation describes the evolution of a document or node within a knowledge construction platform. The more learners approve of and/upvote a document or node, the more it becomes crystalized and stays within the community. The less crystalized it is, the more likely it will be deleted. The two ways that knowledge crystallisation is evaluated is by the amount of continuity points vs. improvement points on the latest version of a node or document. Ex: if a document/node has 5 continuity points and 7 improvement points, the newer version of the document or node will replace the old one.