He's prepared to be wholly unenthusiastic about her gift, whatever it may be, but he's unprepared for what it actually is. He goes visibly still, staring at the inside of the box, before carefully lifting it out and holding it up to the light coming from the nearest window.

He says faintly, "When did you--?" Biting his lip, he brings it closer to himself so he can examine the crystals more closely.

"You never mentioned that you found these," he says unsteadily, after a few silent beats.