This noun designates the amethyst gemstone, a purple or violet variety of quartz. In Revelation 21:20, it adorns the twelfth foundation of the New Jerusalem's wall. Ancient Greeks believed amethyst prevented drunkenness (the etymology means 'not-drunk'). Classical sources describe it as a remedy against intoxication and as a precious purple stone. The multilingual evidence (Spanish 'amatista', German 'Amethyst') identifies this gemstone. John's vision employs the finest jewels to depict heavenly glory, with amethyst's royal purple contributing to the city's splendor.