Please help identify this coral

Here is the pic. Just go to picasa and click on the image. When it opens to the larger one, right click on it and click View Image. When it comes up copy the URL of the image file and click on the button in the Quick Reply area on this page that looks like a mountain and a sun. When it opens paste the URL one the area that says http://.

I am thinking goniopora. Never seen a white one but there's a lot I ain't seen.

Here is a red one.
I thought that too yote but the tentacles seetm very small. the tentacles on my frogspawn are much larger. It's hard to determine scale in the pic though. the goni seems to have smaller tentacles.
That would be the one.

There is a similar coral related to the bubble coral also sometimes referred to as a pearl or grape coral, but that one is totally different (Plerogyra). The one you have is definitely a Euphylia, which is why it looks like a mini-frogspawn.
Thank you everyone. This really helps. The fish store did say it was rare but didn't know what it was called. Much appreciated!