Help ID from Wyoming

[Mkopsa]

Hi Friends!

I found these 2 rocks/crystals when I was out hiking in southern Wyoming (close to Colorado boarder) and need help identifying them! I have gone through my book of rocks, gems and minerals of the Rocky Mountains as well as multiple websites but am unable to identify them! Any help would be GREATLY appreciated! 

I can also add more photos if needed!

-Maddi

Edited April 14, 2021 by Mkopsa
Additional info

[Bedrock Bob]

It is quartz on chalcedony. What the tan mineral is on it im not sure. 

I'm going to call the tan mineral barite. If I am wrong folks will come out of the woodwork to correct me.

I am probably wrong. The crystals don't look right for barite. It does look like a soluble mineral that precipitated on the quartz after the formation of the silica.

Whatever it is it is a neat specimen.

[Mkopsa]

Thanks so much for the help Bob, greatly appreciated!

 

[d_day]

Yep. Chalcedony with quartz. 

[GotAU?]

Try it under a short wave mineral light, the chalcedony I’ve collected glows bright green.

[Morlock]

5 hours ago, GotAU? said:

Try it under a short wave mineral light, the chalcedony I’ve collected glows bright green.

Sometimes you find calcite sandwiched between two layers of chalcedony but only in certain locations. This is called watermelon chalcedony for obvious reasons.

[Morlock]

2 hours ago, Morlock said:

Sometimes you find fluorescent calcite sandwiched between two layers of fluorescent chalcedony but only in certain locations. This is called watermelon chalcedony for obvious reasons.

 

[Idaho Jim]

The green in chalcedony under short wave UV, found in western Wyoming, is from Uranium. I've found quite a bit of it in the Green River Basin.

Jim

[Morlock]

1 hour ago, Idaho Jim said:

The green in chalcedony under short wave UV, found in western Wyoming, is from Uranium. I've found quite a bit of it in the Green River Basin.

Jim

All fluorescent minerals contain minor  "activator" elements such as uranium, lead, manganese, chromium and others. 

[GotAU?]

4 hours ago, Morlock said:

Sometimes you find calcite sandwiched between two layers of chalcedony but only in certain locations. This is called watermelon chalcedony for obvious reasons.

I found these in Franconia with both calcite and chalcedony

[GotAU?]

1 hour ago, Idaho Jim said:

The green in chalcedony under short wave UV, found in western Wyoming, is from Uranium. I've found quite a bit of it in the Green River Basin.

Jim

I think chalcedony has a green florescence itself without uranium, and all the chalcedony Ive ever collected throughout the Mojave glows like that.  But I may be wrong as although I haven’t collected in areas known to contain uranium, it apparently only needs trace amounts of uranyl ions, (U02)2+, to make some minerals glow green.

Edit: Morlock got to it before me, OK, so that explains it and if it only requires trace amounts of uranium it is pretty much everywhere there’s granitic and other intrusive rocks, so that makes sense.

Edited April 28, 2021 by GotAU?

[Morlock]

I really think every gold prospector should have a good battery powered SW lamp in their arsenal. You run into all kinds of outcroppings, ore dumps, etc that can be checked out for fluorescence.

Good multi colored specimens can fetch hundreds of dollars on the market depending on number of colors, patterns, aesthetics. All it takes is one good specimen to pay itself off. A really good lamp can be used during the day as well.

[GotAU?]

7 hours ago, Morlock said:

Sometimes you find calcite sandwiched between two layers of chalcedony but only in certain locations. This is called watermelon chalcedony for obvious reasons.

I meant to post earlier, this is a beautiful specimen! What general location did you find it?  It’s interesting how the calcite intruded into and filled the void inside the chalcedony.

Edited April 28, 2021 by GotAU?

[Morlock]

1 hour ago, GotAU? said:

I meant to post earlier, this is a beautiful specimen! What general location did you find it?  It’s interesting how the calcite intruded into and filled the void inside the chalcedony.

A bunch of this material hit the market about 10 years ago but I haven’t seen anything new since. One dealer was giving the location as Oglala National Grasslands, Sioux County Nebraska and another dealer was giving the location as Scenic, Pennington County, South Dakota. This piece was labeled as the latter.

[GotAU?]

Well those two locations aren’t too far apart! That’s one thing about collecting minerals, a lot of those location IDs are way off. It’s a great little specimen, the way how it must’ve formed is interesting.