Fabergé Easter egg given by tsar is likely to fetch £4m

The world's most expensive Easter egg, originally given by Tsar Nicholas II to his mother, is to be auctioned next month with an estimate of £4m.

The Dowager Empress Maria Feodorovna was handed the diamond-encrusted Fabergé Winter Egg by the Tsar on Easter morning 1913 after he bought it from Carl Fabergé for 24,600 roubles.

It was the most expensive of the 50 eggs made for the imperial family by Fabergé before the 1917 revolution, and is regarded as the most exceptional of the collection.

Embellished with more than 3,000 gems, the egg was designed by a 23-year-old Finn, Alma Pihl, under the direction of Albert Holmstrom, who succeeded his father as the principal jeweller to Fabergé in 1903. Made to symbolise the transition from winter to spring, the shell of engraved, transparent rock crystal opens to reveal a basket of quartz and gold spring flowers. The 14cm (5.5in) egg stands on a detachable rock crystal formed as a melting block of ice and applied with platinum-mounted rose diamond rivulets.

When the Russian revolution broke out in 1917, the egg was confiscated by Kerensky's provisional government and held in the Kremlin Armoury until the 1920s, when it was bought by the Fabergé dealers Wartski. It was sold by Sotheby's to a private collector in 1949 and was not exhibited until 1994, when it was auctioned by Christie's in Geneva. It reached a world record price for any Fabergé item of £3.9m and was bought by an American private collector.

The egg is expected to equal or beat that price when it is auctioned again by Christie's in New York on 19 April. It will be on display at the Pushkin Museum in Moscow before the auction.

The Russian royal family's tradition of presenting eggs made by Fabergé was started in 1885 by Alexander III.

The location of only 44 of the eggs is known. They are held in various private collections, including the Queen's, and in museums.

Pihl's career with Fabergé ended with the revolution. After years of poverty she and her husband left St Petersburg for Finland in 1921. She died in 1976, aged 87.