beryllium n.

hard, lustrous mineral occurring in hexagonal prisms, c. 1300, from Old French beryl (12c., Modern French béryl), from Latin beryllus, from Greek bēryllos, which is perhaps from Prakrit veruliya, from Sanskrit vaidurya-, of Dravidian origin, which might be from the city of Velur (modern Belur) in southern India.

In Medieval Latin berillus was applied to any precious stone of a pale green color, to fine crystal, and to eyeglasses (the first spectacle lenses may have been made of beryl), hence German Brille "spectacles," from Middle High German berille "beryl," and French besicles (plural) "spectacles," altered 14c. from Old French bericle.

word-forming element in chemistry, used to coin element names, from Latin adjectival suffix -ium (neuter of -ius), which formed metal names in Latin (ferrum "iron," aurum "gold," etc.). In late 18c chemists began to pay attention to the naming of their substances with words that indicate their chemical properties. Berzelius in 1811 proposed forming all element names in Modern Latin. As the names of some recently discovered metallic elements already were in Latin form (uranium, chromium, borium, etc.), the pattern of naming metallic elements in -ium or -um was maintained (in cadmium, lithium, plutonium, etc.; helium is an anomaly).