At first glance, these appear to be conventional stained-glass windows with a modern design, but the components of the windows are a bit unusual:
The site of the Grossmünster has been a place of Christian worship since the late 3rd century... Now the Grossmünster has been enriched with twelve exquisite windows by Sigmar Polke... He has given the western half of the church seven windows where the glass has been impregnated with thin slices of agate.
Rockhounding purists might be dismayed by the fact that the geode slices have been "enhanced" by artificial coloration, but the effect is nonetheless quite striking.
Link, via.