Mystery fossil?

[cherturc]

I found this fossil in a dry creek bed in Fayette County Texas. The walls of the creek are about 10-12 ft high. I also found several shell fossils in the same area. The pics are of the top and bottom of the same fossil. Can someone help with identification? Thank you.

[ynot]

This is a mass of calcite crystals, maybe after a fossil but is not possible to tell if or what.

 

Tony

[tmaier]

It's not a fossil, it is a cluster of crystals. Possibly calcite.

[tmaier]

Aaaa! ynot beat me by a few seconds, but we agree.

The geometry of the crystals and a few other tests will help determine what the crystals are made of.

[cherturc]

Thank you so much! I thought that there was something encased in the calcite, visable from the bottom, so that would make it a fossil. Now I know. I appreciate your help. 

[tmaier]

On the bottom, that star looking burst pattern at both the top and the bottom looks like nucleation points of the crystal cluster. That is where the crystalization started to happen to create this cluster. The nucleation seed can sometimes be a fossil, but in this case I don't see one.

[cherturc]

Thank you very much! I've already learned so much from all of your replies. I appreciate it.

[DPS Ammonite]

Very pretty even if not a fossil. A lot of calcite in Texas is fluorescent in both long and shortwave UV light. Let us know what you see when you shine a UV light on it.

[BobWill]

Welcome to the forum. I think most of us would have carried that one home too, even though it's not a fossil. You can expect to find other things that result from geological forces that look like they may have once been alive so don't hesitate to ask about all your finds. We even have a name for some of the ones that are even better at fooling us, pseudofossils. Calcite is pretty common in Texas so that is most likely but a scratch test will verify that. A hardness scale will tell you what scratches what and should be easy to find on line.

[erose]

Classic "dog-tooth" crystals. And as suggested hit it with some ultraviolet light and see if it fluoresces.

[fifbrindacier]

Nice crystal, interesting.