Geodes are more or less round, lump-like formations in rocks that are hollow inside. They are mostly remnants of gas bubbles left behind in lava after solidification. With time they may become partly or entirely filled with mineral precipitates or crystals, very often quartz. Upon erosion of the host rock, the geode, being of harder substance, often comes out whole. When broken or cut open attractive scenery of crystals or agate become exposed. The geode here seen measures 35 cm across and is from south Morocco