Rare Earth Elements in Black Sand

[Capt Nemo]

From the other thread that drifted into REE's being possible in black sand.

I just checked a bucket of Lake Superior black sand with a blacklight. Found little orange specks all over the bucket. Anyone know what minerals glow orange in UV?

I'll have to check the Lake Michigan sands too.

 

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[Jim in Idaho]

Interesting...do they have any afterglow?...phosphorescence? I find all kinds of orange in Wyoming. It's the most common color over there.
The color will depend, too, on the wavelength of the light...long or short. LED blacklights are long....regardless of what they say. Nobody has come up with a true SW LED blacklight. What BL are you using? The rare earth elements often act as "activators" when they are present in other minerals.....they cause those minerals to fluoresce when they otherwise wouldn't. But, the color can be different depending on both the mineral and the particular activator.
Jim

 

[winners58]

many things glow under UV light some minerals that should glow one color glow different because of impurities of rare earths
maybe isolate some and try to identify them under magnification, probably hematite? maybe its alien fungus spores.
Color chart fluorescence of minerals

some of these are just fascinating http://www.mineralarts.com/glowrocks/glowrocks.html

 

[Capt Nemo]

I'm running a cheapo 18" fluorescent blacklight. So longwave.

I'd be picking single grains out of the black sand. Whatever it is, it is close to hematite by weight, so panning won't separate it. The bucket I'm looking at has already been panned to remove the lights. So it might be some form of garnet.

I do have a stalagmite that my grandfather had that glows green with the above blacklight, and continues to glow for about 5-10 min after.

 

[Jim in Idaho]

The only garnets that fluoresce are the Grossular group, that's the group the valuable Tsavorites come from. Most garnets contain iron, which absorbs UV light....they look really dark under UV.
Jim

 

[Capt Nemo]

Just isolated a big grain. It's transparent like quartz! Checked the blonde sand that was panned out and see nothing there. So it's clear and heavy.

 

[Capt Nemo]

Possibilities from the color chart that give orange are:

Barite, Barium
Becquerelite, Uranium
Boltwoodite, Uranium
Calomel, Mercury
Cerussite, Lead
Scheelite, Tungsten
Sphalerite, Zinc
Willemite, Zinc
Zircon, Zirconium

The others would have separated out with the light sands.

 

[Jim in Idaho]

The activator to get orange in Scheelite is Europium...one of the REE's. It's typical for sphalerite to fluoresce orange, and it's often clear. The activator is manganese for orange. It's probably not Willemite, as it rarely fluoresces orange. Cerussite usually is more to the yellow end of the spectrum, rather than orange. Possibly Barite, but orange is rare in that mineral. Becquerlite is a possible, but I don't think it's ever in a clear form.
If I had to guess, I'd say Scheelite, activated by one of the rare earth elements. Europium, or Samarium. Some decent possibilty of it being Zircon, activated by the REE Dysprosium. I'd bet there are REE's in that sand.
Jim

 

[Ragnor]

Some diamonds fluoresce under blacklight from blue to green to orange and maybe even yellow, from what Ive read. It's been a while since I studied up on that.

 

[Jim in Idaho]

Some diamonds fluoresce under blacklight from blue to green to orange and maybe even yellow, from what Ive read. It's been a while since I studied up on that.

That's right, but I think orange is somewhat rare in diamonds. More often blue, or yellow, with occasional green.
Jim

 

[Ragnor]

That's right, but I think orange is somewhat rare in diamonds. More often blue, or yellow, with occasional green.
Jim

Yeah, it's been a while since I have studied on that. I was hard at it for a while untill i finally figured out that my samples were from Texas and not from Washington or Idaho, LOL Took me over a year to figure out where I had collected that black sand.

 

[Capt Nemo]

The activator to get orange in Scheelite is Europium...one of the REE's. It's typical for sphalerite to fluoresce orange, and it's often clear. The activator is manganese for orange. It's probably not Willemite, as it rarely fluoresces orange. Cerussite usually is more to the yellow end of the spectrum, rather than orange. Possibly Barite, but orange is rare in that mineral. Becquerlite is a possible, but I don't think it's ever in a clear form.
If I had to guess, I'd say Scheelite, activated by one of the rare earth elements. Europium, or Samarium. Some decent possibilty of it being Zircon, activated by the REE Dysprosium. I'd bet there are REE's in that sand.
Jim

Given there's lots of manganese staining of the Pictured Rocks to the west, tungsten may be present. Wolframite weathers out manganese to form ferberite, a heavy black mineral of iron, tungsten, and oxygen. So if there's scheelite present, there's wolframite and ferberite also present. I have noted that magnetite seems to act light in the pan when panning. All three of these tungsten minerals are running 6+ for SG where magnetite is 5.3.

I think a trip to the geology department is in order!

 

[Jim in Idaho]

I hope you'll keep us all posted....this is definitely a learning experience for me. Manganese is for sure an activator for orange in many minerals.
Jim

 

[Capt Nemo]

Here's a pic.




Hmm...they don't show very well here. Look for orange specks.

 

[Jim in Idaho]

I see 'em...cool! Wish they were bigger. You need one of those USB microscopes...LOL
Jim

 

[Mudflap]

Cool! If you ever get up to Houghton, MI in the UP check out the mineral museum at Michigan Tech. They have some cool fluorescing minerals from the Superior lakes area.

 

[Capt Nemo]

If you could see it live, you'd see specks about 1/4" apart, so there's quite a bit in that black sand.

I gave Aquila Resources a sample of the wild material and they're going to run it through their lab and give me an assay. They're interested in the black beach sands as part of their heavy minerals program that they're setting up. They're interested in the kimberlite pipes in the UP, and some of the placer that may be found. Though their main focus right now is the "Back 40" mine. The mine will be an open pit/tunnel mine for sulfide gold/lead/copper/zinc. Most of the permits are in place, and mining could begin soon. I did ask about the glacial overburden and if they were going to washplant that material. They may washplant some for gravel for their water treatment plant, but they may be open to allowing amateur miners to run the overburden for gold. We'll see what happens on that front, as they're not digging yet.