Strange Carboniferous Pyrite concretion

[fossilized6s]

I found this piece about a month ago while hiking near Starved Rock, IL with my girlfriend. It is so strange that i thought TFF may enjoy it. I've never seen anything like it and it is my biggest piece of pyrite to date. 

 

It is a large 18cm x 5cm piece of pyrite encapsulating a piece of Lepidodendron fossil from the Carboniferous period. 

 

Unfortunately when i collected it the piece was in a shale wall and when extracting it some of the lepidodendron had broken off and was too shattered to save. But here she is.

 

 

 

Continued....

 

 

[fossilized6s]

[Raggedy Man]

These are common for the starved rock area. The pyrite erodes from the clay layers that are mined in the starved rock mine on the other side of the river to the west.

[Raggedy Man]

Here's a specimen from the quarry that's been cleaned up.

[fossilized6s]

How do you clean your pyrite pieces, Paul? 

[Raggedy Man]

35 minutes ago, fossilized6s said:

How do you clean your pyrite pieces, Paul? 

You can then immerse them in a solution of oxalic acid. This acid can be purchased in crystal form by the pound at many drug stores. To mix a solution, add 1/2 pound of crystals to one gallon of water. Let the pyrites stand in this solution until they have reached the brightness you wish. This can take from 30 minutes to several hours. 

Remove the pyrites, again using rubber gloves, and rinse them in running water. Then neutralize them in a mixture of water and baking soda or ammonia. 

[aek]

12 hours ago, fossilized6s said:

That's an interesting find. I wonder if it would be possible to expose more of the fossil inside without damaging it? Could be risky as the pyrite seems to be very crumbly from that area...

[aek]

11 hours ago, Raggedy Man said:

You can then immerse them in a solution of oxalic acid. This acid can be purchased in crystal form by the pound at many drug stores. To mix a solution, add 1/2 pound of crystals to one gallon of water. Let the pyrites stand in this solution until they have reached the brightness you wish. This can take from 30 minutes to several hours. 

Remove the pyrites, again using rubber gloves, and rinse them in running water. Then neutralize them in a mixture of water and baking soda or ammonia. 

Thanks for the information. I was trying to figure out this issue..