What is this ??

[forgetaboudit]

I can't remember exactly where or when I found this, but I was doing a little spring cleaning and re-found it lol If you click the photos, they get larger.

There is a crevice in it that looks like a geode. The Styrofoam looking parts are rock hard and in the little hole looking things as hard as well. It looks like there is also some quartz in it as well. There are some areas on/in the rock that are real sparkly and glimmers in the light.

 

[GatorBoy]

Looks like fossil coral with some Drusy quartz crystals.

 

[forgetaboudit]

Looks like fossil coral with some Drusy quartz crystals.

Coral in Wi?

 

[Harry Pristis]

Coral in Wi?

Lots of coral pieces were carried into the Midwest by glaciers. They originated from Silurian reefs in what is now Canada. There are so many families and species of reef-building corals that it would take an expert to identify this one with any confidence. Your specimen does seem to be geodized -- largely replaced by silica.