This remarkable emerald weighing 75.61 carats once belonged to Empress Catherine the Great of Russia. The stone was originally a rectangular shape weighing 107.67 carats and later re-cut to a pear-shape to improve its clarity. In 1796 it passed to Tsar Paul I who owned it from 1796 to 1801, then Tsar Alexander I from 1801 to 1825, Tsar Nicholas I 1825 to 1855, Tsar Alexander II 1855 to 1874, Grand Duchess Vladimir 1874 to 1920, Grand Duke Boris 1920 to 1927, Cartier 1927 to 1954, John D Rockefeller Jr from 1964 and then changing hands several times until today in the collection of a distinguished private collector. Estimate $2.3-3.5m. Magnificent Jewels, Geneva 15 May.