A sale at Chippenham Auction Rooms had to be cancelled after thieves broke in overnight by removing tiles from the roof.
The Wiltshire firm is appealing for the trade to be on the look-out for items that may have come from the raid at their Ivy Road address. All of the gold and silver objects about to be offered in the November 9 antiques and collectables were taken, along with a significant amount of the Chinese ceramics, a special feature of the auction.
Objects stolen include a five stone diamond ring set in 18ct gold, an 18ct gold jet and diamond ring, the jet set with eight diamonds in the form of a flower, and from the Oriental section a Chinese 12th/13th Century SongYuan Qingbai dish depicting a phoenix, estimated at £200-£400, and a 13th century Chinese Song/Yuan bowl, believed to be worth over £600.
But the saleroom said that the robbers actually missed some of the best items from the Oriental section and these were set to be offered in a replacement auction on November 16.
Principal auctioneer Richard Edmonds said: ""We hope that by getting this information out there the perpetrators can be caught. We have also circulated pictures of all the items taken throughout the industry so if there is an attempt to sell them the police will be notified immediately.
"It is a real shame when things like this happen but we are able to put on a sale this Saturday [16th] which I am sure will be a success."
Anyone with information should contact police on 101 ext 728295. The incident number is 10977 and the case was being investigated by DC 2215 Debbie Hatch of Melksham CID.