The Duke of Devonshire Emerald is one of the largest and most famous uncut emeralds in the world, weighing an incredible 1383 carats. It is in the collection of the British Natural History Museum. It is a hexagonal crystal, approx 5cm by 5cm.

It was discovered in the early 19th century in Muzo, Colombia.

Around that time, the King of Portugal, John VI, one of the last European absolute monarchs, was exiled from Portugal to Brazil. He returned to Portugal in 1821, leaving his son, Don Pedro, as Governor of Brazil.

Don Pedro moved back to Portugal in 1831, and went around Europe looking for military and political support to reclaim the throne in Portugal. He visited England as part of this trip, where he met with William Cavendish, the Duke of Devonshire.

It would seem that he either sold the emerald to the Duke at this time, or gifted it to gain support.

The emerald was exhibited at the Great Exhibition in 1851 in London, and loaned the the Natural History Museum in 1936. It possesses the most amazing luminosity and exceptional transparency in the uppermost section. The bottom of the crystal, which has some of the host rock attached, is more included.

On a recent visit to London I took a brief detour to view it, in the Vault at the NHM (up the stairs on the right of the famous entry hall), and it is simply breathtaking in real life, in a way that photographs simply can’t convey. The luminosity and enchanting shade of green is wonderful, and as good as one would see in an emerald a fraction of the size of the Devonshire. This is truly one of the world’s great treasures!