Dugway Geodes

Dugway Geodes formed around 6 to 8 million years ago when volcanic activity in Western Utah deposited an igneous rock called rhyolite. Trapped gases formed pockets in the rhyolite, which eventually became lined with chalcedony and quartz from groundwater.

Most Dugway Geodes fluoresce a lime green color due to minute amounts of a secondary mineral that bonded with the quartz when it was growing. The fluorescence comes from uranium salts trapped in the Chalcedony. The level of uranium is so low though, that it is undetectable, and totally harmless.

Dugway Geodes actually moved from the location where they were formed. 32,000 to 14,000 years ago, Lake Bonneville covered most of Western Utah. The lakes wave motion activity eroded the rhyolite and actually moved the geodes several miles away to their current location near the town of Dugway in Juab County, Utah. They are called Dugway Geodes because that is the only place on earth these are found!

Dugway Geodes are found on the edge of the salt flats of the Dugway Proving Ground, these West Desert geode beds are one of Utah’s most popular rock collecting sites. Their convenient location near the gem collecting area of Topaz Mountain make them an excellent companion stop for a family trek to the Thomas Range.

This property is controlled by the Bureau of Land Management (BLM) public lands. Active mining claims exist on some portions of the "geode area" so seek permission from the claim owners before collecting. For more information on BLM public lands under claim contact the House Range/Warm Springs BLM field office at (435) 743-3100.

Until recently, the best known free collecting claim was maintained by Loy Crapo of Delta, Utah. Since Loy’s passing, his family has taken over management of the site. To justify the excavation and insurance expenses of maintaining the site, visitors must now sign a liability waiver and submit a $30 fee per group to collect. In return, the Crapo family is constantly excavating new collecting pits in the clay to ensure visitors have constant access to fresh material.