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Post by fernwood on Oct 25, 2018 14:16:37 GMT -5
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victor1941
fully equipped rock polisher
Member since November 2011
Posts: 1,958
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Post by victor1941 on Oct 25, 2018 16:58:35 GMT -5
Is their any possibility the samples are from a meteorite? My second guess is a fire melted the surface.
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Post by fernwood on Oct 25, 2018 17:29:24 GMT -5
Is their any possibility the samples are from a meteorite? My second guess is a fire melted the surface. I doubt it on the meteorite. The person I got it from had a couple 5 gallon pails of it. The largest one pictured is about 5" long. There were many more this size or larger.
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victor1941
fully equipped rock polisher
Member since November 2011
Posts: 1,958
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Post by victor1941 on Oct 25, 2018 17:46:29 GMT -5
My guess was part of a stony or ejectile rock from an impact. Check out images on google or bing.
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Mark K
Cave Dweller
Member since April 2012
Posts: 2,528
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Post by Mark K on Oct 25, 2018 20:12:17 GMT -5
I am thinking chert or wood replacement. MT is full of it.
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bsky4463
fully equipped rock polisher
Member since September 2013
Posts: 1,696
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Post by bsky4463 on Oct 25, 2018 20:40:24 GMT -5
Ayup I think Mark nailed it, we have lots of chert here...
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Post by fernwood on Oct 26, 2018 5:03:14 GMT -5
Interesting on the chert. Never thought of chert as being that translucent. I can scrape the brown areas off with a knife, very soft.
Thanks
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mjflinty
spending too much on rocks
Member since September 2011
Posts: 356
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Post by mjflinty on Oct 26, 2018 11:43:18 GMT -5
Reminds me of Knife River Flint (ND), even has the same white cortex from weathering on some of them. But, yeah it's some variety of silicate.
Michael
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Post by fernwood on Oct 26, 2018 17:50:48 GMT -5
Did some research on Montana Cherts and Flints. I understand that some use the names one in the same, but most of this has more Flint/Obsidian characteristics. The tan outer areas appear to be limestone. The piece below has a very glassy appearance. Photos taken dry. Still do not show much of the red and purple color. I tried to enhance the photos to show truer colors, hence my floor looks a little pink. 9 10
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Post by Peruano on Oct 27, 2018 8:12:50 GMT -5
I think you need to chip off a tiny bit to see a fresh break. But I will stick my neck out and guess its an atypical obsidian. Although it meets my basic criteria for flint in having the white rind and right texture. But thanks to the post I went searching for more info on weathered obsidians and found a great resource to ponder. Check out the geology home page of Cochise College. Thank you Dr (Mr.) Roger Weller. The site has much geology info and course material in easily digested form, but also photos: 2912 minerals; 1217 rocks, 394 crystals; and 1535 fossils. skywalker.cochise.edu/wellerr/aawellerweb.htmCheck back with us when you have viewed all photos (just kidding). I did not find an easy way to jump from one photo to the next, but the cumbersome format makes you think about what you are looking at rather than doing a media dump so I hope it helps. I bookmarked the site.
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Post by fernwood on Oct 27, 2018 8:36:41 GMT -5
Peruano Thanks. Will check out the link and also try to chip some off.
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