Pyrite disease

[minnbuckeye]

Simple question. Would the application of Butvar B-76 prevent pyrite disease??????? I hope so. I just applied some to the pyrite I collected from the Pella beds, Pennsylvanian of Iowa.

 

[hadrosauridae]

From my understanding, possibly.

 

What I remember about it, is that the pyrite is slowly reacting to oxygen, breaking it down into iron and sulfuric acid which attacks the fossil, eventually causing it to crumble.  If the fossil is sealed, it may halt the process or at least slow it down to a tiny fraction of the rate.

[DPS Ammonite]

Check out discussion at Mindat. They suggest a tight container filled with an oxygen scavenger and a desiccant.

 

Extra credit, pick out a Forum member in this discussion.

 

https://www.mindat.org/mesg-494229.html#494372

[Thomas.Dodson]

I've done a bit of reading on the subject since dealing with pyrite decay and there isn't really a simple answer. From a hobbyist's perspective consolidants can be useful. Consolidants, in theory, work in two main ways against pyrite decay. First, it can be used as a preventative barrier to oxygen and moisture which is needed for the chemical process of pyrite decay. Second, it structurally enhances the fossil so that it may survive some decay/prevent it falling apart. I have consolidated and skipped consolidation fossils from the same site with the unconsolidated fossils eventually exploding while the consolidated ones remain.

 

That said, consolidants are not 100% effective against air and moisture and can apparently be "detrimental" to further treatment of specimens which has made them fall out of favor for pyrite specimens in museums and institutions. (Akiko Shinya and Lisa Bergwall, 2007).

 

"However, treatment in this manner adulterates a specimen and ultimately will be detrimental to further analytical or conservation processes and is not recommended considering the possible beneficial effects are only slight" (Buttler, 1994).

 

I can imagine consolidants might interfere with treatments used to stop decay such as ammonium gas and Ethanolamine Thioglycollate treatment. Still, considering the consolidants are reversible I wonder how detrimental they are.

 

So properly humidity controlled environments and containers as mentioned above are obviously preferable but I think consolidants do have their uses for non-professionals in preventing pyrite decay. Considering we consolidate a lot of fossils anyway it seems a simple step. If you know how susceptible to pyrite decay certain specimens are you can take steps for "proper" dry storage over simple consolidation.

 

Some reading material.

 

https://www.researchgate.net/publication/261713254_Pyrite_Decay_cause_and_effect_prevention_and_cure

 

https://vertpaleo.org/wp-content/uploads/2021/03/Shinya_and_Bergwall_2007.pdf

 

[Bobby Rico]

Hi I never had pyrite disease in my collection this must be to do with storage. I have plenty of ammonites and a couple off trilobite with pyrite . Where I keep my fossils is draughty but not damp at all . I think before treatment of any fossil it must be completely dry , even warmed in the oven to remove moisture . 
I going call our friend @Ptychodus04 because I know he as experience on this subject .

 

I also think you should read the link that @Thomas.Dodson has added on the cure of the disease. I will not say anymore because last time I mentioned it I felt a little ridiculed . 
 

cheers Bobby 

Edited July 6, 2021 by Bobby Rico

[DPS Ammonite]

Whether or not a particular piece of pyrite is going to have problems with pyrite disease, has a connection with the grain/crystal size of the mass. Large solid crystals have few problems. Powdery masses have more problems. The greater the surface area per volume, the easier and quicker the air, water and possibly microorganisms can degrade it. 
 

An example: a pound of iron ground to flour-sized particles placed in a tub of water will rust much quicker than a pound cube of iron placed in water.

[Ptychodus04]

Thanks @Bobby Rico

 

I have had great success with consolidating pyrite that is prone to decay. The trick is to get it very clean and very dry before adding the consolidation material. Since this is already done, the discussion is relatively academic at this point.

 

I soak my specimens in Iron Out for a day prior to drying. This removes any corrosion present. After they are scrubbed clean (the treatment leaves a black film on the specimen) I let them dry for another day. Then, they go in the oven on low heat for a few hours to ensure they are totally free of moisture. After this, they take a bath in the consolidation solution of choice (Butvat B76, PVA B15, Or Paraloid B72). this process has been very good to my pyritized ammonites. I have even employed it to stop active decay present in some specimens.

 

The process may not be preferred for future experimental or analysis purposes but works well for preserving specimens in the collection.

[minnbuckeye]

Thanks @Ptychodus04!! I knew about the other techniques mentioned above. But I just thought to myself, why wouldn't consolidant work. So I tried it. The samples were not prize possessions. In fact I was going to pitch them. Now, thanks to you, I will be educated when I go to use it on better specimens. 

 

Mike

[Mark Kmiecik]

This piece is starting to fall apart and crumble. Very fine grain pyrite throughout the fossil and matrix. Will Paraloid B72 do the job?