Auction houses are on alert after diamonds were switched for paste stones at a saleroom viewing.
Surrey Police are searching for a suspect who was captured on CCTV at Lawrences of Bletchingley.
A police spokeswoman said officers would like to speak to the man in connection with the theft of a pair of white gold single solitaire diamond earrings on November 30 at Lawrences.
Lawrences discovered the switch before the sale and claimed on its insurance to pay the vendor the reserve price of £2000.
It is believed a second incident again involving diamond jewellery occurred at an auction house in the south of England in December.
Surrey Police is not currently in discussion with any other police forces but said if it “receives information that the same person may be responsible for similar thefts around the UK, then that will be followed up”.
The spokeswoman added: “The suspect is described as white, in his 50s, around 5ft 7in tall, of a large build, and was wearing a checked shirt, a purple scarf and a dark jacket.”
Anyone who witnessed the incident, or who has any other information, should call 101, quoting crime reference number PR/45190129933.
The independent charity Crimestoppers on 0800 555 111 can also be contacted.