Treasure Hunting

Although geodes are found all over the world, a region surrounding the area of Keokuk, Iowa is considered by many to be the “Geode Capital of the World”. In fact, this area is so productive and famous among mineral collectors, that Iowa adopted the geode as the state rock in 1967. But what exactly is a geode anyway and what makes Keokuk geodes so special?

Basically, a geode is a rock formation that has a cavity which contains crystal formations and/or some type of banding. The photograph to the left, taken by Daniel Milaczewski and hosted at Wikimedia Commons, is a nice capture of a geode. Don’t let the picture fool you though - geodes can be found with a wide array of coloring and banding depending on what part of the world they are found. In fact, Keokuk geodes alone display an amazing variety of colors, natural bandings, and sizes. This website contains a number of photographs of Keokuk geodes in addition to a plethora of other information on the natural wonder.

While most geodes found are around the size of tennis balls, there are some notable exceptions. The photograph to the right is of a large geode on display in Carefree, Arizona. The glittering quartz inside almost makes it look like it was a secret hideaway for some pirate treasure trove. But really, all that crystal is attached to the interior of the rock cavity and formed naturally.

Typically, collectors cut geodes open so that the cross-section displays the unique banding and crystal formations found in the hollow of the rock. A “matching set” consisting of a geode that has been cut in half can have the flat sides where the cut was made polished. The resulting two pieces can then be used as a unique set of bookends or simply shown off as a decorative accent.