Burglars stole jewellery and cash from a house in Stebbing during the day.
Thieves broke into a locked house in Bran End between 12.30pm and 7pm on Saturday by smashing a conservatory window.
Investigating Officer Dc Nikki Simpson said: "The stolen jewellery was of significant sentimental value to the victims and they are very upset.
"The offence took place in broad daylight and is close to a well-used dog walking route.
"I would ask anyone who may have been in the area at the time to get in touch with me if they saw any suspicious activity or behaviour.”
Anybody that can help is asked to contact Dc Nikki Simpson at Braintree CID on Essex Police 101 or via Crimestoppers anonymously on 0800 555 111.