Stabilize Pyritized (maybe marcasite) Wood in Coal

[Gerry]

Have 2 pieces of pyritized wood (maybe marcasite) from the coal areas of central Illinois-Farmington. One is a slab and the other a branch. Have included photos. I believe the branch may have been coated with clear lacquer. The slab has not been coated but it is deteriorating on the surface.  I had some pyritized snails from the same area from 40 years ago. I had lost them for many years and recently found them and they had disintegrated. Would ike to poish if possible and stabilize the finish.

 

Would appreciate any guidance.  Thanks Gerry

[Myrmica]

I feel your pain.  Pyrite disease is a curse.  You might try ensuring that your specimen is as dry as possible and then coating it with polyvinyl acetate (PVA) which has been diluted in a solvent.  I have had only limited success with that, and have had some lovely pyritized ammonites turn themselves into crumbly sulphate piles.  You might also try putting your specimens in a sealed container with some of those dessicant packs that come with certain random food products?

[oilshale]

Hope this helps:

Pyrite Decay cause and effect prevention and cure.pdf

Pyrite Decay of Large Fossils The Case Study of the Hall of Palms in Padova Italy.pdf

Pyrite Oxidation Review and Prevention Practices.pdf

Use of Ethanolamine Thioglycollate in the conservation of pyritized fossils.pdf

No real cure - you can only slow down the process.

[Thomas.Dodson]

I've had the best luck with consolidating specimens with paraloid. It keeps the moisture out to stop feeding the decay/stop it from starting and as a bonus gives it more structural integrity if there is damage. Just make sure the specimens are as dry as possible before you consolidate. Some people put them in the oven at low temps.

[Gerry]

Thank you all for your quick responses. I will get to work !!!

Best regards,

Gerry