Rory, what if this crack didn't want a rock? Huh? What then? Gosh.

Unfortunately the crack has no choice but to accept the rock, and when it plunks down into it it taps a few times before there's a pulse of bright blue light and then the rock is gone.

And then Rory will feel a weight in her hand and the rock is back there, hanging out in her fingers like it'd never been dropped at all. Did she actually drop it? Was this magic? Weird!