Any info on this .....mushroom?

[Whatisthisplease]

I found this in my garden when I was digging out an invasive weed.  I was keeping some interesting stones in a separate pile to add to stone edging I have around a garden bed.  I saw it, and even covered in soil, it looked interesting.  I removed some dirt and saw it was really lovely.  At first I thought it would be porcelain.   After I removed more dirt I realized that it isn’t.  Both sides are truly beautiful.  It looks like a mushroom to me - the detail is amazing!  I don’t know anything about things like this but came across your website as I was trying to find out more about my find.  Any help and advice you can give would be very much appreciated.  Thank you.

[Pterygotus]

Not a mushroom. Coral, I think.

[Whatisthisplease]

Thanks for responding.  

[Al Dente]

It looks like a modern coral, something similar to Manicina.

 

 

[Whatisthisplease]

Thank you for replying.  Do you have any photos of the back sides of these coral photos?

[Misha]

I agree with @Al Dente 

Here are some pieces of this coral that I have:

The lower piece is very similar to yours although slightly less worn

[Whatisthisplease]

Thank you!