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Jean Sendero
Joined: 20 Dec 2009
Posts: 270
Location: Hudson Heights, Quebec
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Posted: Sep 17, 2014 15:39 Post subject: Preserving Realgar - Is it possible? |
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Hey,
I hope someone can help or confirm the reality. On my last trip to Peru in August, I acquired a stunning 5 cm tall realgar crystal and other smaller ones resting on a sphalerite matrix.
I hesitated before buying this specimen despite its esthetic and color and etc.....simply because from what I know, it is only a matter of time, before this little cutie turn into something ugly.
Having said that, i vaguely remember someone mentioning to me that realgar crystals can be preserved, if not exposed to light but if soaked into ??????......
Is this true or simply words? and if true, what is the liquid or chemical that it needs to be soaked in?
thanks
Jean
Mineral: | Realgar on Sphalerite |
Locality: | Quiruvilca Mine (La Libertad Mine), Quiruvilca District, Santiago de Chuco Province, La Libertad Department, Peru | |
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Dimensions: | 7.0 cm tall |
Description: |
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alfredo
Site Admin
Joined: 30 Jan 2008
Posts: 979
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Posted: Sep 17, 2014 15:54 Post subject: Re: Preserving Realgar - Is it possible? |
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Easy to preserve realgar: Just keep it in a dark cotton-filled box, not exposed in a glass display case. Nothing else is going to help. Well, I suppose you could use a dim red light to display it, with especially green wavelengths filtered out. That would keep it alive for a long time. But if you insist on displaying it in daylight, there is no chemical coating that will help you (except perhaps a nice thick coating of black paint ;))
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lluis
Joined: 17 Nov 2006
Posts: 711
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Posted: Sep 17, 2014 15:56 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi, Jean
I have several realgars from Rumania and from USA; some are around 20 y.o. (in my hands; probably (surely...) older...). They look nice and are well preserved. They are not exposed to light as they are in a Jousi box (were old times...), and in a drawer inside a cabinet. Mainly closed, except when I look at this part of collection.
Taking in account that in mines they resist some thousands of years (not to say millions...), I think that only avoiding the UV would be enough.... (and yes, if soaked in a solution of an UV protector, even better...)
With best wishes
Lluís
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lluis
Joined: 17 Nov 2006
Posts: 711
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Posted: Sep 17, 2014 15:57 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi, Alfredo
Probably a UV coating would help.....
Just many sensitive materials with this, well, resists several years....
With best wishes
Lluís
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kushmeja
Joined: 28 Jul 2014
Posts: 244
Location: New Jersey
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Posted: Sep 17, 2014 16:03 Post subject: Re: Preserving Realgar - Is it possible? |
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I've seen realgar specimens that were coated with a very thin clear coating which helps to prevent the morphing into parealgar & orpiment. I'm not sure what they use for the clear coat, although it's may be some sort of silicone.
I've also heard of people storing realgar in an airtight, oxygen-free container, which supposedly also works because the oxygen is needed for the chemical reaction.
That being said, I've not tried either & I've kept the 2 realgar specimens I have in black sealed boxes nearly the entire time I've had them. I didn't want to risk damaging them, so I went with the safe route.
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Jean Sendero
Joined: 20 Dec 2009
Posts: 270
Location: Hudson Heights, Quebec
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Posted: Sep 17, 2014 16:04 Post subject: Re: Preserving Realgar - Is it possible? |
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Thanks Luis and Alfredo,
I guess, no magic here. Just confirming what I was told.....but I like the black paint idea....can I use red paint instead?
Cheers and I appreciate the quick replies. Peruvian minerals in several instance are a long ways from my areas of better knowledge, Mexican minerals.
Jean
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lluis
Joined: 17 Nov 2006
Posts: 711
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Posted: Sep 17, 2014 16:08 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi, Jean
Thanks for the answer.
And congratulations on the specimens! They really took my heart.
Kushmeja: why is oxygen needed? It does not appear in end product, so, I suppose that it does not play too much a part.... Just asking as a curious chemist (which I am; at least chemist; curious is just character... :-) )
With best wishes
Lluís
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GneissWare
Joined: 07 Mar 2008
Posts: 1287
Location: California
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Posted: Sep 17, 2014 16:26 Post subject: Re: Preserving Realgar - Is it possible? |
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Jean Sendero wrote: | Thanks Luis and Alfredo,
I guess, no magic here. Just confirming what i was told.....but I like the black paint idea....can I use red paint instead?
Jean |
Recommend using Krylon gloss red. BTW, very attractive specimen.
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lluis
Joined: 17 Nov 2006
Posts: 711
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Posted: Sep 17, 2014 16:32 Post subject: Re: Preserving Realgar - Is it possible? |
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By the way, red paint would serve as well as black paint.
Just I agree with Jean and Gneissware: nicer.....
But letting it in a UV free place, would be equally efficient.....and more conservative/environement free... :-)
With best wishes
Lluís
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kushmeja
Joined: 28 Jul 2014
Posts: 244
Location: New Jersey
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Posted: Sep 17, 2014 16:32 Post subject: Re: Preserving Realgar - Is it possible? |
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lluis wrote: | Hi, Jean
Thanks for answer.
And congratulations for specimens! They really took my heart.
Kushmeja: why is needed oxygen? It does not appear in end product, so, I suppose that it does not play too much.... Just asking as a curious chemist (which I am; at least chemist; curious is just character... :-) )
With best wishes
Lluís |
I'm not a chemist by any means, but doesn't the chemical reaction break realgar down into orpiment & arsenolite and/or arsenic trioxide?
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lluis
Joined: 17 Nov 2006
Posts: 711
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Posted: Sep 17, 2014 16:35 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi, kushmeja
No, it turns into pararealgar, that is not orpiment...
Simply changes of crystal net.
More easier...
With best wishes
Lluís
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alfredo
Site Admin
Joined: 30 Jan 2008
Posts: 979
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Posted: Sep 17, 2014 17:08 Post subject: Re: Preserving Realgar - Is it possible? |
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Lluis, Most people assume that UV does the damage, being the more energetic wavelength, but there is some quite old peer-reviewed research showing that in the case of realgar it is green light causing the damage - the wavelength that is most absorbed, so a UV-protective coating won't help much.
I agree that excluding oxygen in this case would not be expected to help either, as the light causes an internal crystallographic change, not an oxidative change.
So, back to Lluis and Jean's red paint idea ... You're right... so much better than black paint!
At one big mineral museum (sorry, I've forgotten which one), they had the cases of light-sensitive proustite, realgar, etc., covered with a hinged wooden board, that was a bit uncomfortable to hold up for long, thus ensuring that interested viewers exposed the minerals to light only briefly.
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lluis
Joined: 17 Nov 2006
Posts: 711
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Posted: Sep 18, 2014 00:10 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi, Alfredo
Interesting that of green light causing damage to realgar...
Well, it is the most absorbed, so, not too much surprise....although it surprises still me....
I will take a look at those articles.
Anyway, then with a light that filters green wavelenght absorved by realgar, would cause no damage.... Ambiance maybe result in somehow reddish, but, well.... who wills anything, should pay anything.... :-)
Anyway, the idea that you mention of the museum, seems to me great.... :-)
With best wishes
Lluís
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Riccardo Modanesi
Joined: 07 Nov 2011
Posts: 618
Location: Milano
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Posted: Sep 18, 2014 03:04 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi to everybody!
I bought in 1983 a realgar relatively big specimen from the U.S. (Nevada if I remember right), and protected it by keeping it in a polystirole box well closed and surrounded by black paper. Then I keep other realgar specimens I have in my collection (much smaller) in the usual small plastic transparent boxes everybody can find readily in any mineralogical bourses. Of course I keep the boxes with the specimens in inside a closet. No light and no air gets through and the specimens are well preserved from losing their red colour.
Greetings from Italy by Riccardo.
_________________ Hi! I'm a collector of minerals since 1973 and a gemmologist. On Summer I always visit mines and quarries all over Europe looking for minerals! Ok, there is time to tell you much much more! Greetings from Italy by Riccardo. |
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Deborah Deitsch-Perez
Joined: 27 Oct 2014
Posts: 5
Location: Dallas
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Posted: Oct 29, 2014 09:33 Post subject: Re: Preserving Realgar - Is it possible? |
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alfredo wrote: | ...At one big mineral museum (sorry, I've forgotten which one), they had the cases of light-sensitive proustite, realgar, etc., covered with a hinged wooden board, that was a bit uncomfortable to hold up for long, thus ensuring that interested viewers exposed the minerals to light only briefly. |
There may be others, but that is how the light sensitive minerals in the Harvard museum are displayed. We saw it a few months ago and it was very effective.
The cover would be set down relatively quickly. There may be others, but that is how it was set up in the Harvard museum and it seemed to work.
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Vitaliy
Joined: 30 Nov 2014
Posts: 52
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Posted: Dec 02, 2014 18:30 Post subject: Re: Preserving Realgar - Is it possible? |
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As also an arsenic mineral collector I do not think a dark box is necessary to preserve the specimens. If the box is translucent or opaque it will help to delay the decay and transformation of it to Pararealgar and then dust. If the specimens are exposed to light constantly then they will transform to Pararealgar quicker and speed up the process of decay.
It is ok to take them out even daily but you should limit the amount of exposure to light. Perhaps not leaving it for hours in open light but rather minutes would a preferred alternative. Even storing specimens in an area where there is shade or less light is an alternative to storing them in a box.
Just as an experiment I put some Realgar/Orpiment specimens in an opaque/translucent box and some other specimens in a black opaque box to see what the difference would be in the long-term.
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Riccardo Modanesi
Joined: 07 Nov 2011
Posts: 618
Location: Milano
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Posted: Dec 03, 2014 08:52 Post subject: Re: Preserving Realgar - Is it possible? |
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Hi to everybody!
I purchased a realgar specimen coming from the US (Nevada? I don't remember by heart now) some thirty years ago, and put it into a small polystirole box covered by black paper. Now it is apparently unaltered. I used the same conservation method for some realgar specimens coming from the Binntal CH. That's what I did. So far it apparently worked enough.
Greetings from Italy by Riccardo.
_________________ Hi! I'm a collector of minerals since 1973 and a gemmologist. On Summer I always visit mines and quarries all over Europe looking for minerals! Ok, there is time to tell you much much more! Greetings from Italy by Riccardo. |
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