The dugway beds have some of the biggest thundereggs ever found. They are found in the north bed and now is a good time to get one as this bed has been freshly exposed. I have dug here for 30 years by pick and shovel and have found just enough to keep coming back. I know where these veins of big ones are, but they have been mostly safe from my pick because of the large amount of overburden needing moved to get at them. The geode angel was kind to me last year and sent the backhoe over to help me out.
Finding a big geode does not guarantee that trophy though. Only a few big ones are good. About one in five are truly spectacular with 'balls' and 'swirls' of druzy quartz. Some of the huge ones have no quartz at all and are just ugly inside. Most bad ones are just too hollow and mud has crept inside through the small cracks in the super thin shell, compromising the insides. This can be truly depressing considering the effort to dig these. While most rockhounds crack the ones they find on site, I save mine for the saw. I am sure I have a few of those big blanks that I will just waste more time sawing. If they were all good it wouldn't be as much fun... I keep telling myself.
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A freshly exposed perlite vein full of rotten (weathered and fractured) eggs. There are a few good small ones in the center of the brown bulls-eye. These are all small, but the flow exposed is a good clue for the big eggs that I know are eight feet below this vein of small ones. All I need to do is move a few tons of overburden. The overburden removal is made easier by the big deep pit dug by a backhoe.
After several hours of overburden removal, a nice vertical 'shoot' of black perlite shows up, embedded with nice 6-8 inch eggs. The giant eggs are just below this black 'chimney'. Notice the ring of white altered perlite (bentonite clay) around each egg. This is caused by the deposition of the quartz in the perlite to the eggs. If there was no white ring of clay... the eggs would be 'blanks' (no pretty quartz) and worthless.
Two big eggs. The smaller one to the left was compromised (full of mud) but the giant 14 incher on the bottom was perfect. That is... it had a nice weight and was well formed. I have not cut these yet (I'm too busy hunting).
The big one removed. Notice how deep the vein with the big ones is. Without help from the backhoe, this egg would be forever unloved.
This exposure was really cool. It was a five feet wide pod of black unaltered perlite rock with a 12 inch thunderegg in the very center. Around the edges of this pod of black perlite was several elongated eggs that were stretched before the perlite flow hardened. These eggs have very small hollows, but lots of pretty agate. These elongated eggs are very strange for the dugways. The egg in the center of the black perlite has a weird gray skin and is very heavy. The big ring of altered perlite around it assures me of a big agate center. It will be fun to see this geode cut. Though not as fun as it was to dig it out. I have never seen such a good exposure of big eggs in such detail.
I had to see what was in the elongated eggs, so I broke a small one on site (it should have been cut) to see what it contained.
A big egg that was too hollow and full of mud. It is still pretty with some gemmy purple/blue druzy quartz, and very impressive because of its size. It will look good in my rock garden.