The École des Mines de Saint-Étienne possesses an important collection of wooden and terracotta crystallographic models (several hundreds). During the 2000s, enhancement and rehabilitation action was undertaken. Several series of Krantz models were identified by the logos and linked to catalogs. The relation of these models to the important work of Paul Heinrich von Groth, in cooperation with the Krantz company, is highlighted. An exceptional element was discovered: a polyhedron with 170 facets, from the cubic system. After a short description of the model, we report on the digitalization work, followed by a description of two duplication methods: 3D printing and precision lost-wax vacuum casting.