Crystallography concepts are usually among the most demanding subjects for Mineralogy students.

Traditional onsite teaching of Mineralogy starts with physical models of crystal polyhedra and frequently also includes the observation of models of crystal structures. These teaching strategies could be difficult to implement under pandemic situations like the present one. But they have also other disadvantages under the usual access conditions as their use by the students is restricted by the number of students in relation to the number of models and by the availability of the models and teaching staff. Additionally, onsite teaching can pose challenges to both students and teachers with temporal or permanent disabilities.

We consider here some possibilities of teaching with virtual models of crystal polyhedra, twinning and crystal structures, based on some of the available freeware options and considering the main concepts taught in the usual Mineralogy syllabus.