Pyrite Disease

[FossilFrenzy]

My fossilized bivalves seem to be turning gold in some areas, and some parts have chipped off . Is this "pyrite disease"? Is it due to being on wooden shelving? I wouldn't say my climate is particularly humid. My great uncle gave these five to me when I was seven, so they are special and I would like to save them

None of my other fossils or minerals are exhibiting these signs?

[Jeffrey P]

That does look like pyrite preservation, though I do not see any real significant deterioration. I've had some pyrite preserved specimens that turned to powder in a few weeks, others that have remained intact for many years. I bury my new pyrite specimens in baking soda for a couple of weeks. That seems to help, but not always. 

[FossilFrenzy]

38 minutes ago, Jeffrey P said:

That does look like pyrite preservation, though I do not see any real significant deterioration. I've had some pyrite preserved specimens that turned to powder in a few weeks, others that have remained intact for many years. I bury my new pyrite specimens in baking soda for a couple of weeks. That seems to help, but not always. 

 

Any way to prevent my others from showing signs? I just noticed this today, but I can guess it's been going on at least a few months?

[Brett Breakin' Rocks]

53 minutes ago, FossilFrenzy said:

Any way to prevent my others from showing signs?

We get this question from time to time ... I'm not sure if the search is just being especially unhelpful with the new release (it's tossing up so many clones of the same info/hits), but here is one discussion that was begun a few months ago:  

 

[Thomas.Dodson]

I don't see any significant deterioration either but if you want to act preemptively you can use paraloid B-72. It's mentioned in some of the older discussions but consolidating in paraloid is pretty effective in preventing pyrite decay by reducing moisture and making the fossil more stable so it can survive some decay. There's also a lot of other information on pyrite decay available through the search.

 

Out of a large batch of Cretaceous molluscs with pyrite preservation I collected a few years ago I recently had some gastropod steinkerns from the site begin a rapid decay. These were the only ones from the site that didn't get the paraloid treatment as they were much stronger than the rest of the molluscs. The problem was recent accidental water contact which kick-started the decay but the originally fragile ones in paraloid got wet as well and were fine. I neutralized the acid in the decaying ones (you can use baking soda like Jeffrey P mentioned) and promptly consolidated them.

[FossilFrenzy]

10 hours ago, Thomas.Dodson said:

I don't see any significant deterioration either but if you want to act preemptively you can use paraloid B-72. It's mentioned in some of the older discussions but consolidating in paraloid is pretty effective in preventing pyrite decay by reducing moisture and making the fossil more stable so it can survive some decay. There's also a lot of other information on pyrite decay available through the search.

 

Out of a large batch of Cretaceous molluscs with pyrite preservation I collected a few years ago I recently had some gastropod steinkerns from the site begin a rapid decay. These were the only ones from the site that didn't get the paraloid treatment as they were much stronger than the rest of the molluscs. The problem was recent accidental water contact which kick-started the decay but the originally fragile ones in paraloid got wet as well and were fine. I neutralized the acid in the decaying ones (you can use baking soda like Jeffrey P mentioned) and promptly consolidated them.

 

Thank you!

Here is a picture of the "worst" decay. 

Would I want to isolate these from the rest of my collection? How far away or what type of container?

[Thomas.Dodson]

58 minutes ago, FossilFrenzy said:

 

Thank you!

Here is a picture of the "worst" decay. 

Would I want to isolate these from the rest of my collection? How far away or what type of container?

I'm not sure on how far to isolate specimens. The sulfuric acid is what damages other specimens and containers but I don't know how bad it needs to get to separate specimens. If you stop further decay you shouldn't need to separate them.

 

If you can't lower the relative humidity or don't want to use paraloid then you can store the specimen in an airtight container with a desiccant. I've also heard of people using WD-40 as a water displacement after you remove the precipitates and acid buildup. Here's some more threads discussing some options on Pyrite Disease.