(IDEX Online) - A Cartier aquamarine and diamond brooch that belonged to Princess Margaret is expected to sell for $54,000 to $68,000 at auction.Queen Elizabeth's younger sister received it as 17th birthday gift from her mother, ahead of her first foreign trip, to South Africa.The Art Deco-style oval hoop is set with circular-cut aquamarines, each shoulder with hexagonal-cut aquamarine highlight set between twin scrolls of brilliant-cut diamonds, mounted in platinum, engraved with the ownership mark 'M' beneath The Princess Margaret's coronet.Royal records show that Queen Elizabeth the Queen Mother bought the brooch in 1947 for ?, ?175 ($235 at today's exchange rate).The sale takes place at Dix Noonan Webb, London, on 23 November.Princess Margaret attracted much negative publicity during her life, especially over her divorce from Earl Snowdon (the photographer Antony Armstrong-Jones). She suffered ill health for many years and died of a fourth stroke in 2002, aged 71.Pic courtesy Dix Noonan Webb