Keeping Pyrite In Check.

[Lmshoemaker]

Hello all, I need help with pyrite; my favorite site is loaded with it and so many of my fossils have pyrite crystals attached to them. I'm tired of looking at old specimens and finding holes in them from where the pyrite decomposed into sulfuric acid, is there any way to prevent this? I believe someone on here told me it's due to water reacting with the pyrite, but I fear keeping water away simply isn't enough because of the humidity of the air. Is there anything I can put atop the pyrite crystals that will keep it from burning my fossils?

[Auspex]

Here are some things to consider and try: LINK

Some of our British members have experimented with mitigating the problem as well (their pyrite seems to be particularly unstable).

[Fossildude19]

Keeping relative humidity below 45% seems to be key - try keeping pyrite fossils in air tight Tupperware type containers, with some type of desiccant packaging in with it.

Make sure the fossils are dried thoroughly after cleaning, maybe in direct sunlight.

Wooden boxes/displays, unless kiln dried, are susceptible to giving off moisture.

More links on the subject:

GOOGLE SEARCH PYRITE DISEASE FOSSILS

Regards,

[Lmshoemaker]

Thanks guys, I'll try your suggestions. Another thing I've been thinking about is using dish soap, I'm not sure if this would prevent the decay of the pyrite, but I believe it would neutralize the acid before it could do any damage. What do you guys think about this?

Edited June 25, 2013 by Cryptidsaurian

[DLB]

Coat with a sealer like cry vac I think it's called.

[Rjhoehl]

Would encasing it in acrylic and making it into a paperweight work? I have never tried this, but it seems to me this would prevent oxygen from making the pyrite oxidize. Maybe someone with experience can weigh in on this.

[kwilson]

Embedding in BioPlastic works. I have used that method for pyritized fossils from here in New York. The sealed container with desiccant also works well (and the specimen is more available for study)

[Lmshoemaker]

What does bioplastic do?

[Blastoid]

Pyrite disease is tough. A friend laid out the cure over on Mindat, it's dead simple, and it works, though we've only tried it on minerals so far. Search for the Mielke Method.

Soak the specimen in water for a few days, scrub with a toothbrush, let air dry for a few days.

This removes the acid and minerals formed by the alteration process, all the way into the deep cracks.

When nice and dry, soak in WD-40 for a couple of days. This displaces the moisture. Remove and dry for a couple days.

Soak in motor oil for a couple of days. This seals it and makes an environment unpleasant to the bacteria that cause the problem in the first place.

Remove and let dry on paper towels, in a warm sunny spot, for a few days.

Problem solved. And no, you do NOT end up with a sticky, smelly mess. The oil drains off completely.

Now, having said all that. I haven't tried it on fossils. The oil will discolor some stuff. You can bet that light matrices will go dark. So try it on something less important.

I hope this works for you.

Right now I'm looking at a lovely drusy pyrite specimen that is decades old and was altering so badly that parts of the matrix were like butter and the box it was in was burnt through by acid production.

I treated it with the Mielke Method last year and it's looking fine.

[PA Fossil Finder]

Try a dehumidifier. We have one in our basement 'cause it used to be really damp. It is amazing how much water it sucks out of the air.

[Fitch1979]

The place I collect is loaded with pyritised fossils, entire ammonites are turned into pyrite, wood covered in pyrite etc. I had the same thing, that w/o proper treatment, they just turn into powder.

After some years, I'm strongly convinced that they should be sealed air-tight with any polymer. I stick to Paraloid B72 wich you need to dissolve in Aceton. 1/10. I make sure the fossil is clean and dry then I soak it in it. It gives a layer that resembles a light varnish over the fossil, is colorless but your fossil apears in to be in a all-wet-condition: it seems wet, darkening it. It's a choice I had to make: even air-tight bags, low humidity .. it all didn't do the trick to me.

have to say .. haven't lost any fossil nemore in years since I use this Paraloid.

would recommend this to anyone! (I'll get some pics here one of these days)

[Lmshoemaker]

Great suggestions all, thank you! When possible, I'll be sure to try some of these out and report back.