Can this be fragged?

[MitchM]

Actually your favia is quite different than your zoos.
The favia deposits a calcium skeleton as it grows. It contributes to the reef structure and dead coral skeletons like that are what make up our "live rock".
Zoos are like mini soft corals which have no substantial skeleton. You could cut down in between the individual polyps and easily frag zoos.
With a favia, you not only need to cut through the polyp membrane, but you also need to cut through the hard coral skeleton.
I would say use a knife first then a chisel, but you are opening up the tissue to infection, there's no guarantee that your chisel would cut where your tissue was cut and you could wind up losing both halves.
Do you really need to frag it?

I couldn't do it, myself.

Mitch