| Gold may have been the first known metal used for ornamentation since Neolithic age, 5000 - 4000 years BC. In Egypt, Mesopotamia, India, China and other ancient countries golden ornamentation had been used since 3 -2 millennia BC. Gold s mentioned in Bible, and in many masterpieces of ancient literature such as Homer's Iliad and the Odyssey. Alchemists called it "the king of metals"; the symbol for gold was identical with the symbol for the sun. The primary goal of the alchemists was to produce gold from other metals. |
| Transition Metal Gold is a trace element; its abundance is 4.3x10-7 mass % in crust and less than 5x10-6 mg/l in sea and ocean water. More than 20 gold minerals are known, the most important of which is the native gold (electrum, copper gold, palladium gold, bismuth gold) which is solid solution of silver in gold from trace concentrations to 43% and contains also copper, iron, lead and more rare the metals of platinum group, manganese, bismuth etc. Chemical compounds of gold are very rare in nature and consist mostly of tellurides - calaverite AuTe2, krennerite (Ag, Au)Te2, sylvanite AuAgTe4, petzite Ag3AuTe2, muthmannite (Ag, Au)Te, montbrayite Au2Te3 and others. Gold is also present in quartz, carbonates, pyrite, arsenopyrite, galena, sphalerite and chalcopyrite. Gold is present in ores as inclusions with usual sizes 0.1-1000 µm; however nuggets with weight up to several kilograms also may be found. Genetic types of commercially important deposits include those of hydrothermal high-temperature gold-arsenopyrite formations, hydrothermal medium temperature quartz-sulphide and gold-quartz formations, metamorphized and weathered deposits and alluvial placers. |