A club member went on a trip to Jacob's Geodes on 3/26/2010,A person mining for geodes. The shale is very soft. The geodes themselves are not particularly hard either. You have to be careful to not hit them with your hammer and break them.
as a side trip from the MAPS conference. Mid America Paleontology Society
Jacob's Geodes is a salvage yard and dig them yourself mining operation in Hamilton, IL. In 2010, one needed to pay $18 per 5 gallon bucket. 5 gallons of geodes is pretty heavy! Something with wheels like a large wheeled wagon or hand truck would be very useful. There are a lot of geodes in bands in the shale/clay. We were instructed to try to find very round ones that would be more likely to be hollow than solid. The hollow ones are considered more desirable. Many geodes were filled with kaolinite, a pure white pasty mineral.
I have yet to have come up with a way to open the geodes. Typically they are opened with a soil pipe cutter, or sawed open. However just
digging them out was fun in and of itself.
Note that Geode Fest is held each fall (Sept 24,25,26 in 2010) . Hamilton, IL Web page
You need to cross a stream from the car parking lot to the quarry unless you drove a big wheel vehicle.
Along the way to the mining area was a vintage Allis Chalmers crawler.
Directly across the Mississippi from Hamilton,IL is
Keokuk, IA. A view of the Keokuk lock and behind it
an hydroelectric plant. All the fish killed in the turbines
made Keokuk a bird magnet. We saw quite a few white
pelicans and other fish eating birds.