In this dissertation we propose a tool for Semantic Data exploration. We developed an exploration model that allows users without any a prior knowledge about the data domain to explore an RDF database. So that, we presented an operation model, that supported by an interface based on the direct manipulation and query-by-example paradigm, allows users to explore an RDF base to both gain knowledge and answer questions about a domain, through navigation, search and others exploration mechanisms. Also, we developed a facet specification model and a mechanism for automatic facet extraction that can be used in the development of facet navigation systems over RDF. The final product of this work is a tool called Explorator that we are proposing as an environment for Semantic Web data exploration.