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Improving Mindat.orgCotton turning grey due to radioactivity?

1st Mar 2018 11:33 UTCReiner Mielke Expert

https://www.mindat.org/photo-876222.html This is pure speculation as there is no reason to assume this. It is far more likely this is due to dust.

1st Mar 2018 13:50 UTCChristian Auer 🌟 Expert

Do I miss something? When he has no clue where it came from why is there a locality name?

1st Mar 2018 14:12 UTCHarold Moritz 🌟 Expert

While I agree with Reiner that the grayness of the cotton is more likely due to the accumulation of airborne crap over the years, cuz I've seen this in old pieces of all sorts and another reason why I hate the fuzzy stuff, people have studied the effects of radiation on cotton, albeit under short but very high doses designed to kill off pests before shipment (quarantine levels). A 2013 paper by Marinus HJ van der Sluijs and Jeffrey S Church "The effect of quarantine-level gamma irradiation on cotton fiber and its subsequent textile processing performance" Textile Journal, did note a slight creamy discoloration to the raw cotton, among other effects not relevant here. If the specimen did that to the cotton it would take a long time (it apparently had it) but would likely be masked by all the other crap such padding collects anyway. Thanks to Fred Davis for finding the paper.

1st Mar 2018 14:44 UTCCharles D Young

I updated the description to note that there was a label that said Liebigite and the mine where it was collected. The specimen is kept in a sealted condiment container. The discoloration is not due to dust. The cotton starts out pure white.

1st Mar 2018 15:14 UTCCharles D Young

Correction. I normally put fresh cotton under my specimens when sealing them in the condiment containers. However, in this case the specimen was so fragmented that I lifted out the cotton from the original box. The discoloration could in fact be due to dust. I will remove that statement.

1st Mar 2018 15:20 UTCReiner Mielke Expert

Hello Charles,

I would suggest leaving out the note about discoloration as there is no scientific bases for it. Also how do you know the history of the sample? For all you know it could have been dirty from the very beginning or it may have been uncovered for a period of time to display it. The comment only serves to add to the misinformation about radioactivity.

Hello Harold,

The level of radiation used in sterilization is many orders of magnitute greater than that you would find in any minerals so the paper is not relevant. It would be like using the effects of the Krakatoa tidal wave to assess the consequences of dropping a pebble in a pond.

1st Mar 2018 15:21 UTCUwe Kolitsch Manager

Thanks, photo is again site-wide.

1st Mar 2018 16:04 UTCHarold Moritz 🌟 Expert

Another paper (thanks again Fred) looked at physical degradation and did find some, but didnt note anything about color. There are too many variables for anyone to conclude that the sample caused visible alteration of the cotton.

Effects of gamma radiation on the

mechanical properties of and

susceptibility to biodegradation of

natural fibers

Waldemar Machnowski, Beata Gutarowska, Jan Perkowski

and Henryk Wrzosek 2012 Textile Research Journal

Reiner, I know, but that's what there is for research. Even those massive dosses didnt have much effect if noted...

1st Mar 2018 17:52 UTCSteve Hardinger 🌟 Expert

In addition the radiation damage might have caused a color change to a cotton colorant/whitener, and not to the cotton itself.

1st Mar 2018 18:24 UTCAlfredo Petrov Manager

Cotton can darken from exposure to SO₂ fumes from decomposing sulphides in a specimen too, which seems more likely than damage from the relatively weak radiation emitted by specimens.

1st Mar 2018 18:34 UTCRonald J. Pellar Expert

Radiation damage is sensitive to distance from the source. Alpha radiation has the most damagein effects over very short distances. Beta can penetrate further but damage is not a great. Gamma is the most penetrating of all but absorption is not high for light density materials. I did not notice any coloration variation over distance from the specimen. The coloration seems to be uniform in the cotton itself. The original source of the cotton may have been unbleached cotton to save money?

1st Mar 2018 20:36 UTCSteven Kuitems Expert

A lot of fine particulate dust/crumbs have worked there way into the cotton fibers. The brown and yellow particles certainly can give the white cotton a slightly darker look.

Steven

2nd Mar 2018 01:07 UTCWayne Corwin

Maybe the dirt on the cotton came from the rock rolling around in it for all these years.

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