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How to remove shale from Pyritized fossils/nodules

Posted by Andrew Zioto  
Andrew Zioto
How to remove shale from Pyritized fossils/nodules
July 24, 2012 05:50PM
I find these (see attached image) in western new york. Ive noticed that there are a lot of people out there asking how to clean these, but most responses are in a "best idea" fashion, rather then a "this is what works" method. Using the method below i have cleaned hundreds of them, and they still look nice and shiny.

I find my best nodules in shale comparable to dolostone in density\hardness.

What you need:
* home depot has everything you need *
- 5 gallon bucket
- strainer
- rubber gloves
- face mask
- well ventilated space
- towel you can ruin
- nail brush
- throw away electric toothbrush $5
- Iron out ($14/bottle (dry powder) **
- CLR $10-$20/bottle depending on size. **

** when you pour these down your sink, you might actually help clean your drain =)

Cleaning method for round nodules of different sizes when you don't want to preserve the matrix:

1) Soak them for a day in water (soften up the shale)
2) Emerge them in a extremely concentrated solution of Iron out. fill a 5 gallon bucket with 3 inches of water and pour in at least 2 cups worth. once you stir it in, the water needs to become clear, or you need more water. soak the nodules in the Iron out for a few hours. Pour them into a strainer. Wearing gloves, cover them in dish soap and massage them together under running warm water. your want them to lightly grind against each other, this will cause most of the shale to fall off and not damage the pyrite. once the soap is all gone, dry them off, and rub each one with a towel (takes time but makes a big difference)
3) Repeat step 2 once more.
4) Soak them in CLR for a few hours. Wash them off good, and than buff with a towel. Shale might still be present in the cracks, if so use the pointy end of a tack to remove it, then soak in CLR again.

Method for cleaning odd shaped nodules when you don't want to preserve the matrix:

1) Soak them for a day in water (soften up the shale)
2) Emerge them in a extremely concentrated solution of Iron out. fill a 5 gallon bucket with 3 inches of water and pour in at least 2 cups worth. once you stir it in, the water needs to become clear, or you need more water. soak the nodules in the Iron out for a few hours.
3) using a nail brush or a electric toothbrush scrub the bejesus out of them to remove the shale, rinse constantly under water to see progress. use the end of a tack to remove shale from cracks/ around the edge of exposed fossils. You will need to repeat step 2 many many times until you have removed the shale.
4) Soak them in CLR for a few hours. Wash them off good, and than buff with a towel.

Method for cleaning pyritized fossils you WANT to leave in the matrix.

1) dip toothbrush in iron out and scrub. rinse briefly under water, dry and repeat, over and over and over. if possible set up your piece in a dish so that only the exposed pyrite is exposed to the iron-out solution, then scrub it every hour or so. change out the iron-out solution ever few hours. Once you have most of the tarnish removed, use CLR on it instead of iron-out. then wash it good with dish soap. (this is how i cleaned the attached image.)
Attachments:
open | download - pyrite cleaned.jpg (373.3 KB)
avatar Re: How to remove shale from Pyritized fossils/nodules
July 24, 2012 08:25PM
Andrew,
Why don't you make that into an article? Have you used this technique to clean anything else?

Rock Currier
Crystals not pistols.
andrew zioto
Re: How to remove shale from Pyritized fossils/nodules
July 25, 2012 12:39PM
what do u mean, "make that into an article"? how do i do that?
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