Quote Originally Posted by Brother Oni View Post
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I thought the cracked Angel face was because it was starving and hence very weak (the Doctor's comment of it being too weak to send River back in the episode).
It's known that the Angels' quantum locked appearance degrades, the weaker they get (see Time of Angels), where they were not much more then roughly human shaped stone masses at first.

Cracking the head/arms/legs off is also related to the sledgehammer comment - it may not be possible to damage them through external force when they're being observed.

When they're not being observed is a different matter entirely, but one we have very little information on (I wonder if anybody's tried tripwires or the like, or simply a bomb with a spirit level on a stationary Angel, thus when it does move, the bomb will detonate).

In any case, all they need is a touch and that little cherub Angel which send Rory back in the first place indicates that mass isn't an indicator of effectiveness, although I concede that wholeness of the physical form will/should have an affect.
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The dialogue was
River: Badly damaged...
Evil Guy: I wanted to know if it could feel pain.
River: You realize it's screaming...

Which to me implies he physically damaged the statue.