kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Dec 12, 2020 12:35:31 GMT -5
I found a rock that has metalic colored areas to it. I found it on the shore of Lake Michigan in SE Wisconsin. I scraped off some of the material. It scraped off like hardened mortar between bricks. I put the scrapings on a sheet of white paper. I then ran a magnet under the dust. Some of the material followed the magnet. Anyone have any ideas as what I have here?
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Post by rmf on Dec 12, 2020 23:21:47 GMT -5
looks like mica on quartz. maybe granite
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lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
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Post by lookatthat on Dec 14, 2020 15:37:50 GMT -5
Thinking molybdenite. It's found in Wisconsin and can be magnetic.
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polaszko
having dreams about rocks
Member since August 2020
Posts: 58
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Post by polaszko on Dec 14, 2020 19:10:06 GMT -5
Molybdenite is slighty flexible - so it wouldn't be scraped off easily. For me it's mica in granite.
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kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Dec 16, 2020 11:33:28 GMT -5
I have put an electrical meter to the area of the rock and it is conductive. Mica is not conductive. It's a good insulator and dissipates heat well. Molybdenum sounds right after researching. To my surprise you are correct it can be found in WI. We would use Molybdenum disulfide as a dry lubricant on machinery that could not use a wet lubricant. Very good lubricant.
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lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
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Post by lookatthat on Dec 16, 2020 12:21:23 GMT -5
Molybdenite is slighty flexible - so it wouldn't be scraped off easily. For me it's mica in granite. OP states that it "scraped off like hardened mortar between bricks"... I'm assuming a good mortaring job. If so, it certainly wouldn't scrape easily. Maybe you need to get somebody new to do your brickwork.
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kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Dec 16, 2020 21:53:34 GMT -5
I don't know what to say to that. :;O( I will just believe its mica.
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Post by rmf on Dec 16, 2020 21:56:12 GMT -5
molydbenite has a black streak and mica has a white streak. they are easy to tell a part.
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polaszko
having dreams about rocks
Member since August 2020
Posts: 58
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Post by polaszko on Dec 17, 2020 7:45:25 GMT -5
Molybdenite is slighty flexible - so it wouldn't be scraped off easily. For me it's mica in granite. OP states that it "scraped off like hardened mortar between bricks"... I'm assuming a good mortaring job. If so, it certainly wouldn't scrape easily. Maybe you need to get somebody new to do your brickwork.
I mean that molybdenite behave more like metal than mortar or rock - it's flexible.
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fuss
spending too much on rocks
Member since October 2018
Posts: 254
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Post by fuss on Dec 17, 2020 11:15:04 GMT -5
Its really hard to tell a lot of times with rounded beach rocks what they are for certain especially since most are glacial transports from Canada. If you really want a better idea you should crack it in half and post a pic of the fresh interior surface, that could be helpful for an ID. But from the basic look of it, Id say a granite or schist are possibilities and the silvery material is more than likely a mica mineral like noted by rmf.
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lookatthat
Cave Dweller
Whatever there is to be found.
Member since May 2017
Posts: 1,360
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Post by lookatthat on Dec 17, 2020 12:25:35 GMT -5
Its really hard to tell a lot of times with rounded beach rocks what they are for certain especially since most are glacial transports from Canada. If you really want a better idea you should crack it in half and post a pic of the fresh interior surface, that could be helpful for an ID. But from the basic look of it, Id say a granite or schist are possibilities and the silvery material is more than likely a mica mineral like noted by rmf. OP stated that the material is magnetic and conductive. I realize that is hard to prove in such a small sample, but I am not aware of any mica deposits that have those properties. Maybe there are --? Do you know of any?
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Post by rmf on Dec 18, 2020 9:55:40 GMT -5
Mica was high graded out of museums during WWII to make electrical insulation for electronics. Non-conductive
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kozman
noticing nice landscape pebbles
Member since July 2020
Posts: 83
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Post by kozman on Dec 18, 2020 22:08:54 GMT -5
I owe you all a big apology! I very sorry. I cannot find the rock being conductive anywhere. Maybe I was picking up some iron seeing the rock is from Lake Michigan. I cracked the rock in half. The silver/black parts are soft. I can scrape it off pretty easily with a pocket knife. The white parts are much harder and very little if any will come off scrapping with the same knife. The white part does have some 1/16" flat parts like a crystal that shine. I'll attach photos of the two halves.
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rocket
spending too much on rocks
Quality slabs for quality cabs in 2022
Member since September 2020
Posts: 292
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Post by rocket on Dec 19, 2020 8:05:00 GMT -5
I owe you all a big apology! I very sorry. I cannot find the rock being conductive anywhere. Maybe I was picking up some iron seeing the rock is from Lake Michigan. I cracked the rock in half. The silver/black parts are soft. I can scrape it off pretty easily with a pocket knife. The white parts are much harder and very little if any will come off scrapping with the same knife. The white part does have some 1/16" flat parts like a crystal that shine. I'll attach photos of the two halves. LOL...as I scrolled down and saw the first photo I immediately thought it was a Christmas cookie...maybe something with shredded coconut with chopped walnuts...now I am hungry...Rocket
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