I got this rock today at one of those places in stores where you can fill a little bag with rocks. I could identify most of the rocks I got but this one is completely eluding me. I've been doing searches for it all evening and I still can't figure it out. It's about the size of a quarter, dark orangish-brown, and it has little black spots. It's been tumbled, so I can't tell what kind of composition it has. What kind of rock is it? Is it even a real rock? If anyone can identify this, I would really appreciate it.