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Geology/What kind of rock is this


I found this rock about a a foot and a half in the ground,what kind of rock is this?is it worth any thing?

Hi Marry,
Unfortunately the image came through really blurry.  All I can see is that it is a black rock, it has some shiny looking, flatish surfaces, and two white surfaces.  Can't tell enough from that to be able to identify it.  There are many things it CAN be.  There are iron rich minerals called "Hematite" that can look much like that.  An igneous rock called "Gabbro" also can have those characteristics.  A "Pegmatite" #a rock with many minerals in it# and "Peridotite" #a rock made up of all very dark, large mineral crystals# can also look like this.

If you could try again with another picture that may help.  

Also, in what part of the country did you find this is?  Very often certain rocks/minerals are prevalent in certain parts of the country.  If I know where you found it, identification can become easier.

Another thing, does it feel heavier than you think a rock of that size should feel.  We all have picked up things and we have an instinctive "feel" for how heavy we think an item should be.  Just tell me if "it feels really heavy for it's size", or something like that.

Does anything flake off when you handle the rock?

Does it look like there are individual "faces" #flat surface#?  If there are, press on one with your fingernail.  Can you leave an indent?  That will tell us the hardness and that might help me to identify your rock.

That should be enough to be getting on with.  I'll be looking for your next question.


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C. Robert Reszka, Jr.


I can answer any general geology question (rocks, minerals, stratigraphy, geomorphology etc.). My expertise is in the geology of the Michigan Basin, PreCambrian, Paleozoic and Recent. I can answer questions concerning mining and petroleum exploration and production and the laws concerning those activities. I can also answer questions concerning stratigraphy of the Michigan Basin. I will also answer questions about mineral and rock collecting in the Basin. I won`t be able to answer many specific questions on hydrology, geophysics or geochemistry. I may be able to answer very general questions in those venues.


I have been working for the State of Michigan for 36 years as a Geologist and a Resource Analyst. I have experience with Subsurface Geology and Petroleum Geology, mining in Michigan, and Sand Dune Mining and Protection issues.

Michigan Basin Geological Society

Decade of North American Geology.
Bedrock Geology of Michigan

BS Wayne State University

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