Any portrait of an Indian prince or princess, from the 15th century to the 20th, is likely to show the sitter draped in fabulous jewellery: ropes of pearls the size of marbles; studded and enamelled belts; daggers and turban ornaments; gold bracelets tied around the upper and lower arms with thick gold thread; anklets and heavy, dangling earrings and nose rings. The words used to describe the stones that appeared in such jewellery evoke lost worlds of glamour and mystery: spinels ‘the colour of pigeons’ blood’, emeralds more beautiful than ‘fragments’ of the sky, diamonds like drops ‘fallen from the sun’.

From ancient times, jewels were prized by India’s rulers and used by them as expressions of their majesty and divinity. In the 1630s the Mughal emperor Shah Jahan, his eyes weakened from weeping for his beloved late wife, Mumtaz Mahal, who had inspired him to build the Taj Mahal, commissioned