THE ROMANOV BRACELET, 2015

This 197.80-carat cushion-shaped rose-cut sapphire from the mines of Ceylon is said to have belonged to Tsarina Maria Feodorovna, wife of Alexander III and mother of Nicholas II. After the Russian Revolution, it was purchased by Cartier New York who made it into a necklace and sold it to the opera singer Ganna Walska. It is now the centre of a bracelet with a design that echoes the facets of the sapphire. In the great Cartier tradition of transformable jewellery, the sapphire can be replaced by a rock crystal.