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Identity HelpPyrite on what?

9th Oct 2016 02:36 UTCAndy Young

So I don't know if this is appropriate for this site, as these might be fossils or man made objects, but they are covered in sparkly, fine pyrite so here goes: I was with ESCONI hunting at Starved Rock Clay Products for fossils and pyrite balls, ( which I got a great bunch of,). And I picked these up because they were pyrite covered. I can't tell whether these are mineralized man-made artifacts or natural concretions with organic matter as the matrix. Let me know what you think.

9th Oct 2016 02:37 UTCAndy Young

9th Oct 2016 02:39 UTCAndy Young

9th Oct 2016 02:59 UTCMatt Neuzil Expert

Look like concretions. There are many places in ohio to get pyrite concretions. Some are flat, rounded, some are spiky or show more crystal form. The middle one in first photo may be some some of trace fossil such as a burrow.

9th Oct 2016 03:14 UTCBob Harman

Agree with MATT. Pyrite concretions, many of them corroding, are quite common in limestone and shale thru out the Midwest. CHEERS.....BOB

9th Oct 2016 06:06 UTCDoug Daniels

The matrix is likely to be shale (well, maybe siltstone...). If you can "flake" pieces off the matrix - shale; otherwise, probably siltstone. Maayyybeee limestone - if so, it will react with an acid (vinegar would work, hydrochloric [muriatic, pool] acid is more definite.

9th Oct 2016 08:49 UTCUwe Ludwig

Are you sure that these are Pyrite? May be it is Markasite. Such (resp. similar) Markasite noodles can be found at the chalk-cliffs of the Ruegen insula /northeast Germany.

Rgds.

Uwe Ludwig

9th Oct 2016 14:09 UTCAndy Young

It's very possible, this was from a clay pit associated with coal with lots of organic material.

9th Oct 2016 14:28 UTCEd Clopton 🌟 Expert

Glad to hear again of ESCONI! I participated in the micromount group there in the 1980s-90s with John & Dorothy Ade, Don & Dorothy Auler, Dan Behnke, John Jaszczak, Andy & Jo Hay, and Jim Daly, among others.

As everyone has said, the concretions appear to be pyrite. Similar-appearing concretions from the shale overburden at the Mt. Carroll quarry in Carroll County, Illinois, often have large, sharp pyrite cubes on the exterior and sometimes have sphalerite at the center. Unfortunately they are quite unstable, cracking up and falling apart after a few months or years. Contrary to what one would expect, the well-crystallized marcasite I collected 30 years ago at Mt. Carroll remains stable, but much of the equally well-crystallized pyrite (both from the quarry proper and from the overlying shale) has deteriorated.

9th Oct 2016 18:35 UTCGeorg Graf

Hi Andy,

in the lower jurassic slates in southern Germany not rarely is found Pyrite or Marcasite, often around/with/beside a shell of a fossil, as Ammonites ect.

Nice specimens.

Best to you and all! Georg

9th Oct 2016 18:42 UTCAndy Young

Thanks Georg! Yes, some of my other examples I see maybe fossilized wood on the interior, with the pyrite wrapping around it. Unfortunately, the pyrite from this location is known to be fugitive, we will see how long they last!

Andy

10th Oct 2016 18:49 UTCJay I. G. Roland

My immediate thought was of fossilized animal droppings or coprolites though I'm likely way off the mark.

Regards,

Jay.

10th Oct 2016 19:03 UTCBob Harman

JAY, I can see why you might consider coprolites, but if they were found here in the US Midwest, they come from an age of smaller invertebrates and a few primitive sharks in a watery environment so VERY unlikely to be coprolites. CHEERS......BOB

13th Oct 2016 19:43 UTCGeorg Graf

Hi Andy,

on photo IMG_2846 and IMG_2853 I see a cirkel like structur. Seems to me to be a negative of an element of the stem of a a Crinoidea.

Regards, Georg

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