Crooks broke into a property in Baker Street between 6pm and 7.30pm on Wednesday, January 31.
A police spokeswoman said that once inside the place was ransacked before the valuables were taken.
The looted items included:
•A gold bracelet (with large and small hoops)
•A gold necklace (with hoops)
•A diamond ring (with a white gold band)
•Three silver necklaces
•A small gold necklace (a thin gold chain with a gold padlock in the middle)
The spokeswoman added: “Anyone who believes they might have been offered one of these items of sale, or has any other information, should contact Hertfordshire Constabulary on the non-emergency number 101, quoting crime reference J3/18/171.”