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gigirus wrote at 2010-04-20 16:19:46
We found a bunch of the stuff that looked like obsidian when we were kids (1960's) in the UP. My mother took it to one of her college classes and found out was actually a byproduct from some type of manufacturing plant. Looks just like obsidian and there was a bunch of it.

Christian wrote at 2013-05-10 22:24:16
I know this is a few years late could also possibly be obsidian. While obsidian is not common in the lower penninsula it can be found in the upper penninsula. There is a picnic area near to Christmas, Michigan in a State Park where it can be found on the beach. I always thought it odd they would choose a beach with glass shards to make a picnic area for children! We also must not forget that due to glacial activity in the area it is very possible the rock could have been picked up by a glacier and redeposited elsewhere. Hope this helps way after the fact!


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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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