beryllium (n.) Look up beryllium at Dictionary.com
metallic element, 1863, so called because it figures in the composition of the pale green precious stone beryl and was identified in emerald (green beryl) in 1797 by French chemist Louis Nicolas Vauquelin (1763-1829) and first isolated in 1828. With metallic element ending -ium. At first and through 19c. also sometimes called glucinum or glucinium.