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Geology/UP Michigan Obsidian


Ashley Tuminella wrote at 2014-01-29 18:01:21
I have also found two very large stones of obsidian in Michigan. I have never had them tested, but comparing it to pictures of obsidian. I know for sure that it is obsidian.  

Tammy Sauve wrote at 2014-09-17 07:03:09
Hello Scott and Robert.  My name is Tammy and I too found a localized, small area of Obsidian rock in Northern Michigan this summer of 2014 with all the same colors as Scott described. They are glassy, fine grained (look semi-precious),dark black,light grey and emerald green in color. I found mine, which totals to the sum of about 200 rocks collected, along side a railroad track.  I surmised at this point that the Obsidian or what ever these rocks may be, must have came from a "rock quarry" as the Obsidian appeared (unknowingly)dumped right along with the other stones from the rock quarry company. This means that what ever rock quarry company that unknowingly dumped these semi-precious stones, must have a very deep basin that they dig rocks from, thus, most likely then an older quarry company? Though, I agree with Scott, in that I also feel that these rocks will come up "unknown".  Why?  Well, strangely enough, not only did I find the rocks in a condensed area but the rocks were scattered in a trail formation, many were imbedded into the ground and not only this but along side this trail of rocks were "freshly" broken off tree branches, not to mention all the skid marks dug into the dirt along this trail.  I do have pictures of this whole scene, the trail of broken branches and skid marks. Taking all this evidence into consideration, I also came to the conclusion that what I may possess may be remnants of a meteoroid.  Feel free to contact me via email at for further questions. Thank you, Tammy  


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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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