Two men, one with an axe, walked into Duncanson and Edwards in Queen Street at about 5pm on Wednesday last week before smashing up display cabinets and grabbing a quantity of jewellery.
Detective Sergeant Bob Richardson believes that the items will be sold off and has called on second-hand retailers to be wary.
He said: "It is likely that those responsible for this robbery will attempt to sell the stolen jewellery on, and so we want second-hand retailers, collectors and members of the public to be vigilant if anyone approaches them with items matching these.
"Our inquiries are continuing to trace the suspects and I would ask anyone who recognises their description or has information that can establish their where-abouts to contact police immediately."
Both men were wearing identical light grey hooded tops with a black chequered pattern and black sleeves.
The man who had the axe, is described as about 6ft, wearing a dark-sleeved top underneath the hooded top and a baseball cap with a light blue peak.
The pair made off on push-bikes and police are appealing for witnesses to come forward as they continue their investigations.