La Régente Pearl — also known as 'La Perle Napoleon' — is considered the largest, natural regular shaped pearl in the world, highly valued by many as the single, most expensive pearl in the world.
La Régente Pearl is the fifth largest pearl in the world, originally weighing 346.27 grains. Emperor Napoleon I gifted the pearl to his second wife, Queen Consort Marie Louise, in 1818. The pearl - previously unnamed prior to its acquisition by Napoleon I from French Crown Jeweler Francois Regnault Nitot — was the centerpiece of a tiara for Marie Louise, the main component of a complete pearl parure. In 1853, the tiara was dismantled and La Régente instead was set as the centerpiece in a pearl and diamond corsage at the request of Queen Consort Eugenie de Montijo, wife of Napoleon III.
More impressive than the pearl's size, is its quality and shape — once described by the inventories of the French Crown Jewels as "a very large pear-shaped pearl, in the form of an egg, flat at the back and very beautiful orient in the front." The first time the name La Régente was used in reference to the pearl was in 1887 in a catalog published for the historic auction of the French Crown Jewels. The corsage was then purchased by Faberge & Company of St. Petersburg, Russia at the 'Vente des Diamants de la Couronne' for Princess Youssoupoff.
Today, La Régente is highly valued as the most expensive single pearl in the world due to its desirable characteristics: the pearl is large in size; has a perfect drop shape; its color and luster are beautiful, described as 'silver/white' with a distinct glow — impressive, even after 200 years.
In 2005, La Régente was sold to an unknown buyer by Christie's Auction House in Geneva for $2.5 million.