Birgit Hammer, a landscape-architect from Berlin had an unconventional idea: for the inner court of the Freiberg castle in Saxony, now housing the world’s largest collection of minerals „Terra Mineralia“, she conceived polygonal granite plates representing the various crystal structures of minerals.
The challenge was giving the surfaces a three-dimensional appearance – crystals are, after all, three-dimensional. To achieve this, Birgit Hammer used a masons’ trick. The plates are devided into separate surfaces, which were then flamed, bushhammered, fine bushhammered or charred respectively distinguishing one from another and creating the optical illusion of three-dimensionality.
A total of 243 crystals were let into the ground. Each plate has a diameter of approximately 2 m and a surface of 4,5 m². They are 12 cm thick. The plates, made of Chinese granite, are let into mastic asphalt with natural stone gravel sprinkled ontop
The original plan was to name each crystal and incorporate additional information in the plates. This plan, however, was dropped in the interest of cutting costs.
Büro Birgit Hammer (in German)