The sale of an enamel-and-gold Faberge egg topped with a diamond-studded cockerel that had been in the Rothschild banking family for more than a century was a record for a Faberge work of art.

A newly discovered Faberge egg made for a top banking dynasty is expected to fetch up to nine million pounds ($20 million) when it is sold in London next month, auction house Christie's says.