Handbook of gold exploration and evaluation / Руководство по разведке и оценке запасов золота

Gold (Au) is a transition metal between Ag and Rg in the chemical series of the Periodic Table. Its atomic number is 79, and atomic mass 196.96655 (2) g/mol, and has only one stable isotope number 197. The gold isotype 198Au (half-life 2.7 days) is used in some cancer treatments. The metal has been known and prized as an object of beauty and for its unique properties of chemical stability, electrical conductivity, malleability and ductility (trivalent and univalent) since mankind's earliest awakenings. As a standard of value against which to appraise the costs of labour, goods, currency and national economy, it has been the standard of many currencies since the world's first coinage in Lydia between 643 and 630 BC. The name for gold is derived from the historic English word `geolo', for yellow and the chemical symbol for gold Au, from the Latin name for gold `aurum' (glowing dawn). <...>