Here is a model of a "real" Topaz crystal. It is based on a crystal measured and drawn by AEH Tutton and shown in his textbook - "Crystallography and Practical Crystal Measurement", AEH Tutton, Macmillan and Co. Ltd, London, 1922, p 231. https://books.google.com/books?id=QWpUAAAAMAAJ&
A second model, idealized to show most faces observed for Topaz, is included.