At the centre of Queen Elizabeth II's Imperial State Crown is an alluring red stone, cut en cabochon. Known as the 'Black Prince's Ruby', it was supposedly taken by Edward of Woodstock, nicknamed 'the Black Prince' the militaristic and wayward son of Edward III, as payment for his military aid to the ruler of Granada. It wasn’t until the mid 18th century that gemologists realised that this beautiful red stone was not a ruby, but was in fact another stone altogether: spinel. Spinels were particularly favoured by the Mughal emperors of India, and several spinel beads inscribed with the names of these rulers who owned them exist in important collections, such as the ‘Timur ruby’, which is part of the British Crown Jewels, and the 500 carat Samaritan spinel in the collection of the Iranian Crown Jewels. Historically, the most important deposits of spinel are in Tajikistan, but additional sources have been discovered in Vietnam and Burma. Spinels range in colour from steely blues, through lavender, lilac and soft pinks, to a bright vivid red, rivalling that of rubies. Due to its relative obscurity in the west, spinel is one for the connoisseur - a hard and durable stone, with a beautiful and distinctive colour palette. It’s perfect for rings, and makes an unusual and elegant alternative to more mainstream gems.