A little tough to tell from the photo. Might be easier to id once it grows out a bit more. I have a coral in my system that was sold to me as a 'chalice' some years ago at a Kamloops swap. It looks more like a green plating monti now that it's grown out. By the looks of your photo it might actually be something similar if not the same as what I bagged. Here's a link that may help. I suspect mine is an Echinophyllia aspera, perhaps that's what you have as well.
http://www.tfhmagazine.com/details/m...lia-aspera.htm
I had some additional links in another thread, but none of them work any longer. There were several other species similar. When I get a bit of spare time I'll try to dig up the thread with valid links.