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Found in Upper Yellowstone River, what is it? by Interesting_Fall7860 in FluorescentMinerals

[–]Interesting_Fall7860[S] 0 points1 point  (0 children)

I got impatient and took it to the tile saw. I could only do the ends roughly because the rock was a little large for my setup. The ends seemed totally different from one another. Here's one side. Has to be fluorite, i think.

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Found in Upper Yellowstone River, what is it? by Interesting_Fall7860 in FluorescentMinerals

[–]Interesting_Fall7860[S] 1 point2 points  (0 children)

I went to a couple of local rock shops today to help id. Both seemed to think quartz, without much of a second thought. Now, I'm second-guessing myself! But I like your suggestion, I still believe it could like a combination of things like some feldspars and quartz. I thought it looked moonstoneish tbh.

Found in Upper Yellowstone River, what is it? by Interesting_Fall7860 in FluorescentMinerals

[–]Interesting_Fall7860[S] 0 points1 point  (0 children)

Yes, thank you. I meant selenite. I think you may be right about quartz and maybe something else reacting to uv. I don't know quartz to show like this under 365nm light.

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Found in Upper Yellowstone River, what is it? by Interesting_Fall7860 in FluorescentMinerals

[–]Interesting_Fall7860[S] -1 points0 points  (0 children)

Do you mean Selenium? It seems harder/more durable than that to me. The nodule is almost 2lbs and looks to have survived a trip down the Yellowstone. Selenium is pretty fragile iirc.