A man entered the shop at around 2.45pm on Wednesday 8th February and stole two diamond rings worth a total of around £60,000.
Police have released CCTV images of a man seen at the shop, who might have vital information.
He is white, aged between 35 and 45, and between 5ft 10ins and 6ft tall. He is of medium to stocky build, with short dark hair which is shorter at the sides.
He was wearing a dark jacket and dark trousers and may have a Newcastle accent.
Images of the stolen rings have also been released in an appeal for information.
Anyone who recognises the man, the rings, or has any information which could help the investigation, should contact Notts Police on 101.
Alternatively call Crimestoppers anonymously on 0800 555 111.