Locally called as "Dugway Geodes", the Dugway Thundereggs are some of the well known and locations in the western states and they have been dug for many decades. Coming from the clay layers (decomposed pertile lava beds), the thundereggs are generally large sized geode-types with sugar-like druzy quartz crystals lining the blue to lavendar agate rims. It's not often to find the thunderggs containing solid and well banded agates while red and purple colors are known but quite scarce. It is not known how much percentage of the Dugway thundereggs contain solid agate or geodes since it's common for them to focus only on the hollow thundereggs that feel quite light for their sizes while heavier thundereggs with solid agates may have been ignored.