A 17th century blue diamond, is expected to fetch in the region of $15 million when it goes on sale in December.
Christie's said on Monday it is putting the Wittelsbach Diamond on to the international market for the first time in almost 80 years.
"The appearance of a large blue diamond, among the rarest of colors, with a history that can be traced back to the 17th Century and 300 years of royal connections will surely be a thrilling occasion for all collectors of ... rare jewels," said Francois Curiel, international head of jewelry.
According to Christie's, King Philip IV of Spain selected the finest gemstones for the dowry of his 15-year-old daughter, the Infanta, upon her betrothal.
It is on public display at the auction house in King Street, St James's, London, on Friday 5 December and from Sunday 7 to Tuesday 9 December.
