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Fluorescent Arizona Fossil Wood


Boomtree

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Hey all. Decided to check out some of the Arizona fossil wood I got from the DoBell Ranch under a microscope. Got board and put my UV light to use. I shined it in the 5 gallon buckets and on the large pieces. I was surprised to see some pieces glowing a bright green, and continue to glow after a short time using shortwave UV. After some inspection under the scope, the fluorescence seems to be coming from a clear or white botryoidal mineral that looks very similar to the white, fine grained matrix. In fact, I didn't notice a difference between it and the matrix at 30x until after I shined the UV on it. BTW - I forgot to put on a glove with UV light - wont do that again! Anyone know what is making it fluoresce?

 

 

 

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SW UV green = Fluorite 

 

 

Edit: Completely wrong. Proof im useless at 3am.lol

...I'm back.

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9 minutes ago, Raggedy Man said:

Fluorite 

Awesome! Totally unexpected. Was hoping to find some mineral associations like quartz, amethyst, or groutite. I found quartz and groutite, but had no idea this fossil wood could have fluorite. Thanks.

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Not floorite.

Many of the agates in the western US have trace amounts of iridium uranium which causes the bright green fluorescence.

Wood from the chinle formation is mostly agatized.

Darwin said: " Man sprang from monkeys."

Will Rogers said: " Some of them didn't spring far enough."

 

My Fossil collection - My Mineral collection

My favorite thread on TFF.

 

 

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The areas of yellow fluorescence are from uranyl ions (uranium) in chalcedony (not fluorite). Check mineral hardness with steel knife blade which will not scratch chalcedony but will scratch fluorite. Yellow/green fluorescence in chalcedony from uranium is very common in the western US.

See article: https://pubs.geoscienceworld.org/minmag/article-abstract/79/4/985/86116/uranium-and-uranyl-luminescence-in-agate?redirectedFrom=fulltext

My goal is to leave no stone or fossil unturned.   

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Very nice! :)

And , yes, chalcedony is by far the most likely candidate.

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7 hours ago, Boomtree said:

Awesome! Totally unexpected. Was hoping to find some mineral associations like quartz, amethyst, or groutite. I found quartz and groutite, but had no idea this fossil wood could have fluorite. Thanks.

Sorry I was reading a different chart with the use of activators and manganese in relation to phase contrast microscopy. I apologize for my stupid mistake. I really need to better organize my files. I should used this site https://www.vaughns-1-pagers.com/science/fluorescent-mineral-colors.htm as I normally do for my finds from time to time when I can't remenver myself. 

...I'm back.

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8 hours ago, DPS Ammonite said:

The areas of yellow fluorescence are from uranyl ions (uranium) in chalcedony (not fluorite). Check mineral hardness with steel knife blade which will not scratch chalcedony but will scratch fluorite. Yellow/green fluorescence in chalcedony from uranium is very common in the western US.

See article: https://pubs.geoscienceworld.org/minmag/article-abstract/79/4/985/86116/uranium-and-uranyl-luminescence-in-agate?redirectedFrom=fulltext

Great, thanks. I enjoy the scientific journal articles. I noticed some of the silicified surfaces do have a feint green, as though there are traces of uranyl ions. The bring green on the specimen in this video isn't coming from the agate itself, rather it is from what I now believe is botryoidal chalcedony on the surface, and mixed in with the matrix. The loose sand and dirt has been removed from the specimen, and all the white you see is an ultra-fine grained matrix, the individual particles of which can't be seen under a 30x stereoscope. It is very hard. Thanks everyone. Awesome!

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4 hours ago, Boomtree said:

from the agate itself, rather it is from what I now believe is botryoidal chalcedony 

Chalcedony = agate,  they are different names for the same thing. Mostly regional usage.

Darwin said: " Man sprang from monkeys."

Will Rogers said: " Some of them didn't spring far enough."

 

My Fossil collection - My Mineral collection

My favorite thread on TFF.

 

 

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6 hours ago, ynot said:

Chalcedony = agate,  they are different names for the same thing. Mostly regional usage.

Okay. Agate is a form of chalcedony, but I don't think they are perfect synonyms. I don't believe all chalcedony is agate, but I'm not a degreed geologist so maybe I'm wrong. I was using 'agate' to describe the main body of the fossil wood, which has red, blues, and whites that are common to the Arizona fossil wood from the Chinle formation. I was using 'chalcedony' to describe the clear, botryoidal crystals growing on the surface of the fossil wood, on the matrix, and in the matrix.

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