Dugway Agate Geode # 111
approx. size 13.5cm width x 9.5cm height x 6cm depth
855 grams
Some of the Dugway geodes, found near the community of Dugway, Utah, are lined with chalcedony that produces a lime-green fluorescence caused by trace amounts of uranium. (This geode doesn't)
Dugway geodes are amazing for another reason. They formed several million years ago in the gas pockets of a rhyolite bed. Then, about 20,000 years ago they were eroded by wave action along the shoreline of a glacial lake and transported several miles to where they finally came to rest in lake sediments. Today, people dig them up and add them to geode and fluorescent mineral collections.