A thin band of white light wrapped itself around their hands, and Hermione felt a tingle of warmth.  He murmured a second enchantment, and the band of light vanished, appearing to sink into their skin.  As Hermione watched, a mark appeared on her wrist.  Indistinct at first, it took a moment to form, and when at last it turned solid black, it had taken the form – not of individual chains, like Augusta Longbottom’s mark, but rather an intricate, six-strand Celtic knot, all intertwined.  It was beautiful. 