The theft happened on Wednesday at Gordon's Jewelers located in the Concord Mall.
Investigators say the thief struck up a conversation with a sales associate, then asked to see a 2.08 carat diamond ring.
The clerk handed the man the ring, and police say he then sprinted from the store, through Macy's, then out of the mall.
Police say this same suspect struck at two Zales Jewelry stores, both on December 2nd, in Columbia and Frederick, Maryland.
Anyone with information pertaining to this case should call Troop 1 at 302-761-6677 ext. 305 or Crime Stoppers at 1-800-TIP-3333.