This swiss cheese is a group of colorful pyroxene crystals containing small blobs of garnet and surrounded by larger areas of the same garnet. Did the pyroxene grow around the garnet, or vice versa? Actually, this texture was formed when both minerals grew simultaneously in a solid rock. Very hot igneous rock intruded impure limestone, heating the limestone and causing its minerals to react and form the garnet and pyroxene.

Crossed polarizers