The break-in happened in the early hours of Saturday at Shapes Furniture and Auction House on Bankhead Medway, Edinburgh.
Police Scotland detective constable Joyce Gunderson said: "This was a brazen crime which has led to the theft of antique jewellery worth thousands of pounds being stolen.
"We are appealing to anyone who was in the area around the time of the incident, who noticed anything suspicious, to contact police as a matter of urgency.
"Similarly anyone who believes they have been offered the stolen items for sale, or has any other information that can assist our inquiries, should also get in touch."
Anyone with any information should contact Police Scotland on 101, or make an anonymous report through Crimestoppers on 0800 555 111.