The suspect stole a diamond he was viewing at Joint Venture Jewelry in the 200 block of Grande Heights Drive on Dec. 28.
The thief is described as heavy set. He was wearing a white long-sleeved t-shirt, black pants and a Duke baseball cap. He also had tattoos on both hands.
The suspect left the store in a dark colored sedan.
"After exhausting all leads, we're hoping citizens can help solve this case and return thousands of dollars worth of property back to the showroom," said Capt. Don Hamilton of the Town of Cary's Criminal Investigations Unit.
No one was injured and no weapon was shown.
Anyone with information on the crime is urged to contact the Town of Cary Police Department at (919) 469-4012 or Cary Crime Stoppers at (919) 226-CRIME.