Looking at this specimen found in the Mississippi in MN it appears to have mineralized and turned to rock. Heavy for the size, also appears it’s hollowed from what I could see through one slit in the middle. Also wondering what the black staining is?
Nice piece of rock containing a geode. Thanks for lots of pictures to help viewers. Fossilized wood normally has some visual evidence of a cellular structure, even though the cells are usually mineral-filled. I don't see that in this case. My guess, as a naturalist but not geologist or minerologist, is that it is a thick vein of quartz that has had softer rock worn away from it, leaving this piece and the wearing process has rounded the edges of this piece. Maybe a real expert on the subject will weigh in.
Oooooh okay that makes a whole lot more sense to me now, and I appreciate your info and for replying to my thread! It’s a super unique find for me and I like I thought of it being a geode, wonder since it’s pretty hollowed out, if it would be worth cutting down the middle, the long way to expose the inside of it??