Tiny geodes found, lake/mchenry county Illinois.. What are they, Crystals minerals Options

[GRenee1980]

Hello all! Former Colorado resident now in Illinois. I live on the border of lake/mchenry counties in Illinois, about 10-15 miles from Wisconsin border. I've recently found several tiny geodes in a nearby farm field. I am curious as to what they are. Tiny/ nickel sized geodes with white druzy crystals. Unsure if Quartz or calcite. I haven't tried to dig any.. All those found have been lying on surface. Any thoughts or opinions? I've scoured the Internet and cannot find anything. I know that western IL and southwest Iowa are keokuk geodes.. But I'm 3-4 hours away in Northeast Illinois. Photos included

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[MikeS]

Welcome to the forums GRenee1980!

Your geodes look like Calcite to me. Nearby limestone would indicate Calcite should be around. I have a sure fire test for you. Rinse a lesser piece in water then let it dry. Put a few drops of vinegar on it. If the vinegar starts to fizz or make bubbles then you have Calcite (calcium carbonate). If you can't get a bubbling reaction then it is likely Chalcedony(Quartz).