Criminals went into a house on Mornington Crescent in Cranford, Hounslow, and made off with a quantity of gold on Friday (April 15), according to police.
The crime is believed to have taken place in the afternoon between the hours of 2.30pm and 5.30pm.
The Heston policing team is appealing for any information following the incident.
Officers are urging people who may have seen or heard anything suspicious to call Hounslow police via 101 and quote this reference 0507639/16.
Police are also appealing for help with information after a 16-year-old boy was stabbed in Inwood Park, Hounslow following a fight with a group of youths on Friday evening.
Statistics from the Metropolitan Police recently revealed knife crime, gun crime and rape were on the rise in London, which was put down to 'better reporting'.
Hounslow CID are also urging any witnesses or anyone with information to call the team via 101 or through Crimestoppers anonymously on 0800 555111 or online.