Valuable jewellery including a large solitaire diamond was stolen from a house in Dunstable Road, Dagnall.
Burglars broke into the house through a downstairs window between 9am and 8pm on Saturday.
They ransacked the house before leaving with a gold band with three rubies and two opals, the diamond in a crown setting and an antique gold ring with a topaz stone.
Police are asking anyone with any information or if they have been offered the items for sale to come forward.
Call Thames Valley Police 24-hour non-emergency single number 101 and ask to speak to Det Con Justin Harris at Aylesbury Police Station.