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Post by fernwood on Jan 25, 2022 1:48:48 GMT -5
These were in a bag labeled Thomsonite. Would some of them be considered low grade Thomsonite? Most do not have the bulls eye pattern associated with Thomsonite. Most do not look like the photos I have seen. There appears to be some other materials in the bag. Thanks.
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Post by rockjunquie on Jan 25, 2022 7:03:12 GMT -5
I see quite a few that are. I don't know about all of them.
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jan 25, 2022 10:43:41 GMT -5
Yes I see about 5 or 6 that are for sure. Some of those could be polished as is in the matrix for nice samples for display but Thomsonite is hell to get out of the matrix without breaking it. Keith at the Beaver Bay Rock shop does a lot of lapidary in Thomsonite check his site for photos. I was at the outcrop on the North Shore in 2018 and material could still be collected.
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Post by fernwood on Jan 25, 2022 10:47:34 GMT -5
Thanks. This was collected prior to 2002.
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Post by Jugglerguy on Jan 25, 2022 10:55:45 GMT -5
They might be prehnite. Prehnite in the U.P. of Michigan looks an awful lot like Thomsonite. In fact, it is sometimes called "U.P. Thomsonite. Prehnite is usually green but in the Keweenaw Peninsula, it can have microscopic copper in it, giving it a pink color. One variety is called "Patricianite" Here are some articles that will tell you more: Patricianite or NotThe Difference Between Thomsonite and Prehnite
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jan 25, 2022 10:57:52 GMT -5
Those look like they were collect on the beach. Your not that far to the North Shore so if you ever want to see the outcrop let me know and I can put you in contact with a friend who lives in the area who can show you the spot. It is on state property.
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Post by fernwood on Jan 25, 2022 11:01:23 GMT -5
Yes, another bag with some of the same is marked paradise Beach, Grand Marais. I don't know if it was MN or MI, but some of the bags say the number of miles they had traveled so far on their major rock collecting trip.
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Post by Jugglerguy on Jan 25, 2022 11:07:41 GMT -5
Yes, another bag with some of the same is marked paradise Beach, Grand Marais. I don't know if it was MN or MI, but some of the bags say the number of miles they had traveled so far on their major rock collecting trip. Paradise beach is in Minnesota.
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Post by fernwood on Jan 25, 2022 11:11:34 GMT -5
I didn't know about the one in MI until I saw this:
Grand Marais is an unincorporated community and census-designated place in Alger County in the U.S. state of Michigan. It is located within Burt Township on the shores of Lake Superior, and the community is the eastern gateway to the Pictured Rocks National Lakeshore via H-58.
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jan 25, 2022 12:30:53 GMT -5
That's the one. The outcrop is just off highway 61 about 7 miles south of Grand Marais Minnesota. Please note the basalt is very hard and your not going to get them out without power tools. In the Spring you might find some on the nearby beaches. My wife has a very nice piece of thomsonite in basalt I will post a photo if I can find it.
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