I'd say the only must is that she has to look like cracked stone and have darker horns, nails, claws, nipples and dong. The colour I'd like isn't set in stone, so while grey is the obvious choice for a statue, you could try a greyish purple or blue... See what sticks. So that and any other additional details (such as the a dragonlike neck/torso/under side of tail, or glowing eyes instead of stone eyes) I'll leave to peoples best judgement.
I'm open to seeing many takes on this and maybe Fraenir as well as I see a lot of potential with gargoyles in the Fantasy map. If I didn't suck with blender, I'd likely have made dozens of gargoyle variations myself.