In the IDW continuity, the Dresden Diamond is a valuable jewel displayed at a New York museum. Due to long-term exposure to radiation, the Dresden is a bright green color.
Michelangelo first learned of the Dresden when he was mistaken for a computer expert named Carl, and became involved in a jewel heist. He managed to make his way to the Dresden using his ninja agility, and smashed the case in order to set off the alarms.
He snatched the Dresden and escaped out a window, only to be confronted by Detective Kara Lewis, who demanded the jewel. When confronted by the leader of the heist gang, Michelangelo pretended that he was going to hand the Dresden over, only to punch the man out with it. He then gave the diamond to Lewis.