The Coal Project, now discontinued, was an experimental knowledge archival system built using the Internet Archive’s services. The project stores knowledge in a way that enables the information to be accessible in a structured form to historians, analysts, and other researchers. It is distinct from projects such as Wikidata and MusicBrainz that aim to collect knowledge, in that a primary purpose of the Coal Project is to archive this information. It is also distinct from projects such as the Internet Archive that primarily archive unstructured documents, in that the Coal Project archives knowledge in a way that can be understood by computers. The Coal Project can supplement archived documents by making the knowledge they contain available separately from the documents themselves, as well as by placing documents within the historical context in which they were created by making connections between the documents and other archived records. By preserving ephemera along with details of their context and provenance, the project aimed to freeze, or "crystallize", knowledge, such that both the content and context of documents would persist and be found valuable in the future. (The name of this collection originated as a metaphor to describe that, from the popular misconception that coal becomes diamonds over time.) The project has since been discontinued.