This science kit is an adventure ready to be discovered! Geodes were formed millions of years ago when prehistoric volcanoes erupted and gas bubbles were trapped in the lava. The result is a science phenomenon-incredible crystal caverns within each exciting geode. When kids gently hit one of the geodes with a hammer, it will break open to reveal a hidden mineral treasure. Includes safety goggles and 6 geodes from one mine. Geodes range in size from 1.5"-2".