We got our first taste of geodes and fossils in Utah last summer.
He continued to check on us throughout the four hours and gave us little hints. There were all types of people there -- families with little ones, some with hammers and some searching the quarry floor, and even a couple guys with their own professional tool set. As far as I could tell from the periodic bubbles of excitement ("mommy, I found one!" "oooh, look at this one"), everyone was having a successful day. We're definitely going back!
Before the trilobite-hunting climax, though, we had an arguably much more adventurous experience finding the Dugway geodes. Dugway is a well-known geode hotspot, where many of the commercial geodes in the US (like the ones at the Del Mar Fair) are mined. So we expected that the digging could be good. What we didn't expect was that the drive there and back would be so noteworthy!
The road to Dugway is the actual historic Pony Express Trail. The scenery was classic. But the wildlife... on the way there we saw a falcon, an eagle, and numerous pronghorn, who stood right alongside the road watching us drive by. And on the way back... get this -- over 200 pronghorn and about 150 wild horses! Yes, I said "Wild Horses"! How do I know they were wild? Because the Utah Rough Guide specifically mentions the mustang packs that run between these mountain ranges. Apparently there are many in western Utah, and a web search turns up lots of info about them. I particularly like this photo site. I so wish I got pix of them, but the disc was full by then. So stupid.
We actually wound up going geode-hunting almost by accident. While browsing the souvenir shop at Timpanogos Cave, we stumbled on the "Rockhounding Utah" book, which is just packed with places to find all kinds of neat rocks and fossils and gemstones. We decided that Dugway seemed like a good bet, and it was a day trip out of Park City where we were staying. Going by the rockhounding book and some good directions from the web, we got up extra early and ventured west.
A GPS is a good idea for this trip, because once you're off the main road, there are dirt paths going off in every direction. We were able to find it without a GPS, because I was able to match the shapes and sizes on the downloaded pix to the windy dirt roads, but it wasn't without quite a bit of backtracking and reorienting. But once we made the final turn, the quarry was obvious -- there were huge hills of ashy and multicolored gravel, and as we looped up over the hills we found ourselves overlooking enormous pits, one of which was about four stories deep and housing a steam shovel! But no one was around, save one car which was leaving as we arrived.
Looking around the site there were lots of crazy-looking volcanic-like rocks scattered about. Avoiding what was obviously a commercial claim, we explored another pit for clues. Eventually, Mel just sat down and started digging. We knew roughly what to look for -- the geodes would be under a layer of clay. Geodes were originally gas bubbles within the molten volcanic rock. They rose up as high as the clay and the outer shell cooled, forming a hollow ball. Later on, mineralized water seeped through cracks in the shell, and depending on the minerals, formed glassy films and crystals inside the shell.
Digging down, I thought it neat that you could tell how mineralized the dirt was, because the dirt was colorful -- Within the ashy stuff, the dirt was also pink, brown, white, yellow, and blue! Sometimes you would pull up a colorful semisolid clump and know that "under different conditions" that clump would have become a really cool agate geode. We also dug up quite a few broken geodes. But about 30 times in the four hours we were there, we pulled up a nice solid piece that was somewhat round and sometimes a tad lighter than it should have been...
We've still to open most of them. I cracked one open with a soil pipe cutter -- a standard method -- and it's one of the prettiest we've ever seen. (It's the blue-ringed one) In general the geodes we found are much more colorful than any of the commercial geodes we've seen. They're much more irregular, but for us that just makes them interesting!