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Identity HelpRadioactive green crystal, Juab Co Utah

27th May 2017 05:43 UTCAmy Morishita

Hi, I'm new here but I just found out yesterday that a lot of the specimens I collected were hot. I have a sample of pitchblende and this beautiful green and white crystal (I see a few blue, possibly azurite crystals with my macro lens) is at least as hot. I borrowed a geiger counter that is old and needs calibration, so I can't say exactly how hot. My radium dials and cobalt were not as radioactive if that helps. Does anyone know what this is? I saw a picture of torbernite by accident and thought it looked like it. I'm buying a new geiger counter to replace the one I lost, but I'd love to know exact readings asap.

We found this along with obsidian, malachite, a very yellow, also hot stone...hundreds of pounds brought home. All but a few stayed outside. I have a dosimeter and nothing has shown up. My pitchblende stays inside multiple containers, but a few specimens that are hot have been sitting in areas not occupied much, so I'm not too worried. We were in and around Eureka, Silver City and the area near the Mammoth mine, though not on private property.

Thanks for any help!

Amy

27th May 2017 06:16 UTCAmy Morishita

-- moved topic --

27th May 2017 11:32 UTCReiner Mielke Expert

I think your geiger counter is giving you false readings. This looks like malachite to me.

27th May 2017 16:50 UTCDonald B Peck Expert

I don't know, Reiner, but in the first and third photos, the blue green mineral looks to be interlocking prismatic in habit, and it shows a few good cleavage planes. Could the yellow-green stuff be autunite?

Amy, Welcome to mindat. Do you have a UV lamp? Most uranium minerals are fluorescent -- autunite a yellow green; torbernite none. If you have torbernite (the darker green), which I doubt as I don't see any foliation, it is a phosphate and will dissolve in HCl.

27th May 2017 18:48 UTCBrent Thorne Expert

Hello Amy,

I have collected in the Tintic area many times. Most of the minerals that you will find there are sulfides, carbonates, sulfates, and arsenates. There are a few phosphates and vanadates with some rare tellurates and tellurites. The only confirmed uranium mineral is metazeunerite found at the Mammoth mine and the Centennial Eureka mine. I agree with Reiner that most likely what you have is malachite. The metazeunerite is very rare and only a few specimens are known.

28th May 2017 00:18 UTCAmy Morishita

Hi everyone, I went to a community college where a friend works and got a proper reading. It's 3 microsieverts/hr, but this man wasn't into minerals, so didn't have much else to offer. I have cheap short wave and long wave flash lights, this rock fluoresces under long wave. The green crystals don't fluoresce, but the yellow and other colors do. I would absolutely love it if I found something rare. Hope everyone is having a good weekend!

28th May 2017 17:29 UTCDonald B Peck Expert

Amy, what color was the fluorescence?

29th May 2017 07:50 UTCIan Nicastro

I tested a handful of thumbnails from the Mammoth Mines, none were hot, but nothing had any yellow or truly metallic minerals that I handled. Meanwhile all the Tiffany stone I've been sent from Spor Mtn was very weakly hot, about 1-2x baseline. I've discovered quite a few surprises in my collection, often due to microlite crystals hiding on pegmatite minerals, and zircon sold as other things. In my experience the popular ludlum model 3 geiger counters with pancake probe used for beta rad can't give you an accurate mrem/hr reading straight off the machine dial, you have to do a bunch of math comparing the units performance to certain known standards that you wouldn't have access to unless you worked at a univ or company in the field, I honestly just go off of counts per min and how many times greater than environmental baseline it is. Don't use the tube probes for gamma rad, as minerals give off beta. Don't forget that U and Th decay to Radon gas so storing large amounts of rad minerals in poorly ventilated rooms is a bad idea. I've seen secondary copper minerals on the same matrix with radioactive minerals before form Africa or Australia I believe.

30th May 2017 20:25 UTCAmy Morishita

The white parts, fluoresce purple/blue and there are bright yellow/green spots around the green crystals. I'm going to be getting a new geiger counter in later this week. Could only afford a Radex but plan to upgrade after we close escrow on our house. I have everything outside, except for my radium watch dials, cobalt and pitchblende, which are tiny and in layers of plastic, glass, then metal and in an area of the house no one uses. We have a problem with radon gas here, so we test. I have dosimeter pens and nothing has shown. I think I'd like to get some more sensitive film badge types, that I used when working with x-ray.

31st May 2017 05:11 UTCDoug Daniels

By the way.....anything you have with cobalt should not be radioactive (unless there's some uranium/thorium minerals mixed in with them). The nasty one would be the isotope Co-60, which apparently is something you want to be about 1000 miles away from. It is not naturally occurring, rather is artificially made.

5th Jun 2017 22:28 UTCAmy Morishita

That's scary, it's definitely NOT supposed to be Cobalt-60! It shows such a low level that I am thinking the container it came in may have been contaminated by the original owners's handling of it, along with a lot of other radioactive substances he owns. It's registering at .10 uS/hr over background. I'm new to this, so I'm still learning a lot. I love radioactive minerals and really want to expand my little collection. I don't get out to rockhound as often as I'd like. Is there anyone here on this group who lives in Utah that knows of some nice groups? I am mildly autistic (not noticeable except for the social anxiety), so down to earth people who don't mind my frank honesty, that's not really otherwise appreciated in Utah, would be best.

6th Jun 2017 00:04 UTCThomas Lühr Expert

Amy,

I'm not sure if i understand you right, english is not my native language. Do you find it scary that your cobalt can not be Co-60 (because it's natural) and is slightly hot anyway ?

The reason is that cobalt minerals are often formed together with uranium minerals and occur close together (the so called Ag-Ni-Co-Bi-U paragenesis). So your cobalt ore sample may well have a small amount of pitchblende (or an other uranium mineral) on it. Take it as a natural "contamination" if you want to see it in this way.

6th Jun 2017 01:49 UTCDoug Daniels

Thomas -

she had originally asked about her cobalt-mineral samples not being radioactive, which is what one wants. If your cobalt-bearing sample is radioactive, due to the cobalt, then you may have a problem. However, with natural samples, this problem is highly unlikely. As you mentioned, there may be some small amounts of a uranium mineral mixed in, making it appear to be radioactive. But, it is not due to the cobalt.

6th Jun 2017 07:00 UTCIan Nicastro

Doug I've been in the same room as a cobalt 60 source while it was in shielding, we used to have one at a research institute I worked at. The cinder block walls were lined with lead, and the door to the room didn't open directly onto the source, you had to go around a corner that had mirrors to visually check that the source was in it's shielding to enter the room. Even with the source kept down inside the shielding the gieger would still be screaming in the room, I heard it was about the equivalent of a chest xray every 15 mins while it was in the shielding, but we only would be in there for a min or two to set something up and then leave the room to bring the source out of the shielding while no one was in the room. It was used to cause DNA damage in biological samples to conduct research on.

6th Jun 2017 16:30 UTCDonald B Peck Expert

Amy, if you have only natural minerals, do not worry about cobalt-60. It does not occur in nature. It is the product of nuclear reactions and is completely synthetic.

6th Jun 2017 16:40 UTCBrent Thorne Expert

Hello Amy,

There is a club in Salt Lake City, Utah called Mineral Collectors of Utah. The website is http://m-c-u.org . We meet at the Sprague Library in Sugar House every third Wednesday of the month at 6:30 PM. The website will give more details.

Brent Thorne.

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