Spinel: “The Great Imposter”

Perhaps the most stealth gemstone in history, the spinel has endured centuries of mistaken identity. Often confused for a ruby, spinels exhibit the same brilliance and rich pigeon’s blood colour that is so intrinsic to rubies – spinels also come in shades of pinks, purples and blues. Many famous rubies in crown jewels around the world are actually spinels, including, the Black Prince’s “ruby,” a 170-carat red spinel featured on the Imperial State Crown of England. Despite their long history of confusion, spinels are magnificent gems in their own right. Their nearly perfect crystal structure and brilliant flash of deep colour render them rarer than rubies. Click through the slideshow to discover some of Sotheby’s Diamonds' most beautiful spinel creations. – Ashley Flight

Lead image: Queen Elizabeth II attends the State Opening of Parliament at the Palace of Westminster. © newsphoto / Alamy Stock Photo