Originally Posted by Deagol
Hi all, i'm a fairly well read and well educated man but this one has me beaten - found this out in the back yard and I can't figure out how it came to be. It looks like some kind of 'regular' rock wrapped inside a an iron containing rock.
Any geology experts can help me?
My 2 cents. Under heat the minerals rose to the outside and formed a crust. So it just appears to be a rock inside a rock.
Or could have actually been a rock that got covered in sediment of a different type and over time worn pressure formed a rock on outside.
There are probably a number of processes that can do this.