Semantic Crystal is a query interface to Semantic Web knowledge bases that requires a formal and graphically displayed query language. The name is an homage to Anselm Spoerri's InfoCrystal, a graphically-based query tool for Boolean and vector space information retrieval (A. Spoerri: Infocrystal: A visual tool for information retrieval management. In proceedings of the 2nd Intl. Conf. on Information and Knowledge Management, Washington, D.C., 1993.)
The domain-independent interface can be used for querying any OWL-based knowledge base that is locally stored or on the web. It displays the ontology model to the user as shown on the left side of the image below, which is a very advantageous feature for the end-user. A query is composed by clicking on elements in the graph and selecting elements from menus. Once an element has been selected, the interface presents it on the query graph dashboard on the upper right side of the user interface. The user can then continue assembling the query either on the dashboard or in the graph representation of the ontology model.
E. Kaufmann, A. Bernstein, "How Useful are Natural Language Interfaces to the Semantic Web for Casual End-users?", in proceedings of the 6th International Semantic Web Conference (ISWC 2007), Busan, Korea, 2007, pp. 281-294. PDF