A jewel thief stole a diamond choker and bracelet from a hotel room in Kingsway, Brighton.
The pieces, whose value is unknown, were taken from the room some time between Saturday, April 24 and Saturday, May 1.
PC Alvin Lee said: “The matching diamond choker and bracelet were of great sentimental value to the victim, belonging to her late mother.
“If you have been offered the chance to buy the jewellery or know who may have stolen it, please contact us immediately.”
The choker and bracelet are described as matching, each with a row of three diamonds.
Anyone with information is asked to contact Sussex Police on 0845 60 70 999 quoting serial 1165 of 01/04 or anonymously to the independent charity Crimestoppers on 0800 555 111.