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Unusual find . . .can someone help me identify this?

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I'm a novice when it come to identifying rocks, but I have a keen interest in it.  I was doing some landscaping and removed a lot of dirt and rocks and came across what is in the picture.  I immediately thought it was some type of fossilized bone, but there is no color variations and it is very heavy.  If you do think it is a bone and not some type of rock, how old could it be and from what?   Any and all help appreciated.


asked Aug 27, 2016 by April (180 points)

3 Answers

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I have a couple of questions for you. Where did you find this rock. My backyard ineastern Pennsylvania would be good enough, or a riverbed in Scottsdale, Arizona. This will give us geographic information sometimes crucial to identifying your sample. The picture is not the best but, why do you think it is fossilized bone?

The outer rock appears to have fossils in it. Small marine type animals and plants, maybe corals. That would indicate limestone. The blue and white layers in the rock there indicate a sedimentary formation which could form from any minerals in the area. Maybe this is from a lakebed. The glaciers which advanced over this continent could move it and deposit it. For instance, I live in Lower Michigan but there are rocks from Lake Superior region moved 300 miles south here.
answered Aug 28, 2016 by Weasel (58,930 points)
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I live in northern California about 1 hour from the Oregon border and the Mad River runs very close to my property.  Fossils that have been found at the mouth of the Mad (about 15 miles from my house) are from the late Pleistocene Epoch, around 200,000 years ago, but to my knowledge no coral has been found .  The specimen is about 6 1/2 inches long.  I thought it was perhaps a fossilized bone simply because I'm not trained in how to identify fossils of any type.  At first I thought it might have been some old cement but the end of the specimen looked organic and the striations for my untrained eye also looked organic

Thanks for your help in identifying this.


answered Aug 28, 2016 by April (180 points)
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For what it is worth your rock appears to have quartz crystal in the layers. That would be a silica rich water which may have evaporated and left quartz layers. There appear to be alternating layers of different materials. Your rock appears to have been subjected to pressure which shifted the layers which then recemented itself somewhat misaliigned. That is interesting too. 

Here is a picture of another couple of rocks. Puddingstone in number one The other rocks in it were subject to glacial disturbance and later became cemented in by the silica rich waters. The second picture has a Lake Superior agate. It formed in an air bubble in volcanic magma. The same waters that formed up quartz subjected to different pressures and circumstances become agates. This agate formed in the Superior region but was moved to my yard by glaciers. This 250 lb. puddingstone was formed by that billion year old agate, other stones and alluvial flow from a receding glecier.  Ice three miles deep that's 15000 feet thick subjected that rock to great pressure. Picture number three is mudstone also found in my yard. The university professor identified it as mudstone almost two billion years old. If you can enlarge it you can see the layers of silt cemented together. You can find really cool rocks in your backyard. A rock shop can help you identify it further.


answered Aug 29, 2016 by Weasel (58,930 points)
Thanks again Weasel.  The pics and your commentary were very helpful.  There is a 'rock shop' about 40 miles from here and next time I'm out that way I'll take it in to see if they have any more information.

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