Two men, one armed with an axe, walked into Duncanson and Edwards on Queen Street at about 5pm on Wednesday last week before smashing up display cabinets and grabbing a quantity of jewellery.
Among the items taken were 11 watches, including 10 made by Rolex, and various rings.
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 other second-hand retailers, collectors and members of the public to be vigilant if anyone approaches them with items matching these.
"Our enquiries are continuing to trace the suspects and I would ask anyone who recognises their description or has information that can establish their whereabouts to contact police immediately."
Both were wearing identical light grey hooded tops with a black chequered pattern and black sleeves.
One of the men, who was seen carrying an 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.