Batman: Death and the Maidens #7 (2004)

Death and the Maidens, Chapter Seven
Having awakened from either a trance or a dream, Bruce is unsure whether what he saw with his parents was real. But as he examines the cave, he quickly deduces that he's been robbed. he substance that was taken is more valuable than any earthly metal or gem... a crystal with only one useful purpose. Believing that R'as al Ghul has stolen the kryptonite from his cave, Batman chases the Demon's Head down. His nemesis warns him that his daughter Nyssa seeks to create a moment that will unite humanity in mourning... hoping that she will find her own emotions again in a global outpour of grief.
Release Date: 2004