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For all you amatuer geologists out there, here's a little assignment for you. What kind of rock is this? It's a curious orangish-brown color. I found it out in God's Garden scattered among the many broken fragments of chalky white limestone that make up the cliff on which we live.
It's very hard and perhaps twice as heavy as a limestone of similar size. It has this mysterious little hole on one side.
Near the hole a chunk of the rock has fallen away to reveal a black layer and what look to be slivers of wood or some other fibrous material (difficult to photograph without a microscopic lense).
Anybody know what this is or want to hazard a guess as to what the mystery rock might be?
Hint: It's not any kind of igneous rock.
6 comments:
Nope- I have no earthly idea, not even to take a guess. The real question is do YOU know? Or is this some kind of sick joke? :) ha ha
I spent several hours researching this. I actually do know what this is.
Er, are you sure Kate or Ollie isn't the source of this "rock"?
I remember Mike Davies, our geologist next door neighbor, had "petrified sloth poop in his collection" -- it looked a lot like this!
But I'll guess sandstone, although it looks too dark and the texture isn't quite right. -- Michael
It's petrified dog dung! GROSS!
Ok- so I keep thinking about this rock...I'm guessing it's sedimentary due to the river. Sandstone, maybe, but the round shape has me hoping it's a GEODE! Trevor will be on the first flight there if you have geodes in your yard! He spends hours wearing goggles and smashing rocks in the driveway hoping for a geode...
I would say it's red limestone but the weight makes me question it. It would help to know if it would fizz when in contact with HCl. I would say some kind of sedimentary clay because of the color but the fibers you describe don't match, unless it is fibers that were trapped in the sedimentary layers. My random guess would be petrified wood. (I know, I'm a freak...too many Geology classes to have a normal response!) -- Cheryl
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