One way to tell for sure is to give it a light ding with a fingernail - if it "rings" it's not cracked, if it goes into a dull thuddy end, it is.
It does look suspiciously like a crack from the photos, but I wouldn't like to say yay or nay.
If you turn it around in the light, a crack will show up as a bright, reflecting edge inside the walls of the piece.
It's really easy to tell when you've got it in your mitts!