I found a petrified log that has a lot of iron in it how much might it be worth?

So I was on a large hill and I slid now a very steep side of it that was about 100 feet. I wasn't hurt but I noticed a large red rock was under me. I also noticed it looked very similar to the bark of a pine tree. It turns out it's petrified wood that weighs about 20 pounds. I googled it, and it turns out the rock in that area is red because it has a lot of iron in it that has rusted over the years.it is a very unique rock and I'm wandering how much money could I get for it?