9" Large, Whole/Unbroken Keokuk Geode

Large, Whole/Unbroken Keokuk Geode #33967

This is a large, 8.6" wide whole/unbroken geode from near Keokuk, Iowa. Experience the thrill of breaking your own geode and being the first person to see what is inside. Most of the Keokuk geodes contain quartz crystals of various sizes plus many other secondary minerals. There is no telling what is in this geode, though it is a "rattler" which is a good sign, usually indicating a large crystal interior.

You can break your own geode using a hammer, cut it if you have access to a saw or we will open it for you using a specialized geode cracker, rubber band the two halves together and let you be the first to peer inside. The geode cracker method is much more likely to create a clean break with less changes of fragmentation. If you want us to crack it for you prior to shipment please indicate so in the shipping instructions.

We can not provide any guarantees on what maybe inside the cracked geodes, and already cracked geodes can not be returned.

Unlike most geodes that form in volcanic rock, Keokuk geodes are found in sedimentary rock. They started out as concretions of mud that formed around organic material about 340 million years ago. The outer shells of these concretions were subsequently replaced by chalcedony and the interiors of the concretions were dissolved, leaving a hollow space into which quartz crystals could grow. Most geodes are 2 to 5 inches wide, though specimens as large as two feet across have been found.

Keokuk geodes contain a variety of minerals, but quartz is dominant in most. Many geodes are filled with clear to white quartz crystals. Micro-crystalline quartz, or chalcedony, whose component crystals are too small to be seen with the naked eye, forms the outer shell. Chalcedony layers also encrust the interior walls of many geode cavities, covering the surfaces of the earlier-generation quartz crystals in a variety of colors, including white, gray, blue, yellow and orange. Calcite is also a common mineral in many geodes, though seventeen other minerals have been identified in Keokuk Geodes, including pyrite and sphalerite.

The area around Keokuk, Iowa is sometimes referred to as “the geode capital of the world". In 1967, these geodes were even named the official state rock of Iowa. Geodes have been collected from the Lower Warsaw Formation within about 100 miles of the city for over 150 years.

Here is a video of us breaking a large, Keokuk geode with the geode cracker.

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