Petrified Palm Wood Or Coral?

[Siriptitous]

Hi Everyone.

We found this beauty in our garden along with lots of gorgeous agates and other fossils. Near antigo wisconsin.

I made a few cuts with our lapidary setup.

Thought it would be coral or palm

[Plax]

chert after oolitic limestone? Did the previous owner dump fossils and minerals on your property or is this material native to Wisconsin?

[Carl]

I like chert after oolitic limestone - neither palm fibers nor coral.

[Siriptitous]

chert after oolitic limestone? Did the previous owner dump fossils and minerals on your property or is this material native to Wisconsin?

Very native to Wisconsin. Devonian sea. :-). We live next to a field and the old rock piles are literally in my back yard.

[Siriptitous]

This has a hardness of microcrystalline quartz, (mohs 6.5-7) so it could be agatized chert. We've found a lot of it in a variety of colors. Some with definite patterns. Lots of corals and shells.

[Siriptitous]

Just studied up on chert. Very interesting stuff. Thank you for the help. :-)

[Plax]

it was only an opinion but glad it got you down the path to the facts, you're welcome

[janislav]

I'm confused. Neva WI is in N Central WI. The only Devonian rocks outcropping in WI are a narrow band along Lake Michigan N and S of Milwaukee. If this is fossiliferous and Devonian, it is most likely not from a local rock outcrop. It might have been glacially transported to the present location as well, but few rocks from further north would have Devonian fossils either.

[Siriptitous]

Yes, you are correct. There are no outcropping of bedrock near here, but tons of glacial deposits. Still its very fun to dig through "Ma Natures" garbage piles. LOL :-) Specially when its in your back yard. My nephews have a blast and it facilitates a strong interest and desire to learn more, which is why we joined this site.

[John K]

Glacial deposits in Wisconsin are not limited to formations from only northern origins. the above graphic (modified from Clayton and others, 1992) shows the differing movements of the various glacial lobes that have moved across the state.

I've found shark teeth from Western Minnesota/NoDak in Western Wisconsin, and coral fossils on the east side of the state (most recently in glacial gravels on top of the basalt cliffs along the Jump River, just north and a little west of Wausau).

That said, I agree that this latest piece is oolitic limestone, metamorphisized into chert. Are you going to cut it into finished stones? That might be interesting...

[Siriptitous]

That said, I agree that this latest piece is oolitic limestone, metamorphisized into chert. Are you going to cut it into finished stones? That might be interesting...

Hi John, :-). Yes, i think i'll slab and polish the oolitic limestone that has metamorphisized into some very attractive chert. Might make some nice cabochons too.

[Tethys]

i would call that oolitic chert. The upper part of the Ordovician Prairie du Chein formation has multiple horizons of oolites and oolitic chert. The more colorful pieces are very suitable for lapidary material.

[Herb]

I would agree with Tethys

[Diceros]

Good call, Don!