RockCheck is a free educational tool that allows users to learn more about rocks and their classification. It is the key for the teaching of the rocks within the natural science subjects in the formal school system. The application is based on the standard classifications of rocks, and it is adapted to the needs of the general public. The content of the application is based on the standard concepts of geology, which makes it suitable for all ages. It contains over 400 questions and links, which provide additional explanations of the concepts and procedures. It is a key for the understanding of the basics of geology. The RockCheck application is a tool for the teaching of the basics of geology, which is an important part of the curriculum for the students of the geological sciences. The application is an aid for the teaching of the basics of geology, which helps the students to understand the principles of geology and the characteristics of the various rocks. It is an educational tool for the students and for the teachers, which can be used in the classroom and in the classroom by the students themselves. It is a free application, which is an aid for the students of the schools and for the teachers. It is an educational tool for the students, for the teachers and for the parents.