jewel that is in fact not a ruby but one of the world's largest polished red magnesia spinels (see ruby spinel). The unfaceted, 361-carat stone is set in the imperial state crown of England. It is inscribed with the names and dates of six of its owners. The earliest is Sh─h Jah─ng┤r, 1612, and the latest is A?mad Sh─h Durr─n┤, 1754.