Metallurgy tycoon Viktor Vekselberg bought Forbes' collection, including 15 Faberge eggs, last year.
The St. Petersburg Times reports Valentin Skurlov points to a number of signs on the egg known as Spring Flowers. They include an inventory number --never placed on items Carl Faberge made for the Tsar and his family -- and the low quality of the workmanship.
Spring Flowers was described in a 1917 inventory as being made of silver and bearing a sapphire, Skurlov said, while the egg in the Forbes collection is gold without a sapphire. The Forbes Spring Flowers, named after a basket of flowers inside, first appears in the records in 1961.
Czar Nicholas and his family gave Faberge eggs as gifts. The Imperial eggs, like much of the Czar's property, were seized by the Soviet government and later sold.