Pyrite (Coral?)

[gcaruso]

I found the plate yesterday while hunting for trilobites at the Penn Dixie Site near Buffalo, NY. It's filled with pyrite and bits and pieces of other things. I was wonder, though, if the bits that turned into pyrite are fossil coral, something else, or nothing at all. Sorry if this is a silly question...I'm pretty new to this.

[tmaier]

Is that mud, or mudstone?

If that is just mud, then what I would do is extract some pieces and clean them for better examination. If it's mudstone then just cleaning the surface might revel more detail.

You might find some loose specimens near where you found this matrix... nature has extracted it for you already.

[MarcoSr]

I collect an Eocene site that has lots of pyrite in the matrix. I see all the time micro shark and ray teeth embedded in the pyrite. I sometimes see teeth or small bones and vertebrae that have a fine pyrite coating. But I've never found a specimen where it looked like the pyrite replaced the original fossil. But others will have to speak if pyrite can replace or only coat a coral fossil.

Marco Sr.

[gcaruso]

It's mud stone, I think (not mud). I'm just curious what the pyrite patterns are of--it definitely looks like something.

I was also wondering if anyone knows how to go about preserving pyrite or a piece like this.

Many thanks, Gregg

[Ludwigia]

Yes, pyrite can in some cases replace the entire original substance of a fossil. There are 2 pyritized beds at Penn Dixie. The Penn Dixie Bed, which is made up of crumbly schist, is well known for its small pyritized goniatites, brachiopods, bivalves, gastropods and nautiloids. Yours could well be from the Big Tree Bed, which yields among other things pyritized sponges, blastoids and bivalves. So some of those bits may be sponges. The thing is that pyrite concretions in sedimentary stone are often just that: pyrite which has grown around a miniscule organic germinal point. They also take on the craziest forms. As tmaier suggests, it would help for identification to extract some or all of the concretions. But maybe you'd just like to leave it as is. It sure does look pretty!