Gold

Gold articles are found extensively in antiquity mainly as jewelry e.g. Bracelets, rings etc. Early gold artifacts are rarely pure and most contain significant silver contents. This led to the ancients naming another metal - electrum, which was an alloy of gold and silver, pale yellow and similar in color to amber. Therefore, early gold varied from pure through electrum to white gold. The symbol for gold is Au from the latin aurum meaning shining dawn. Stone age man learned to fashion gold into jewelry and ornaments, learning that it could be formed into sheets and wires easily. However, its malleability, which allows it to be formed into very thin sheet (0.000005 inches), ensures that it has no utilitarian value and early uses were only decorative. As gold is a noble metal, being virtually noncorrosive and tarnish free, it served this purpose admirably. Gold is widely dispersed through the earth's crust and is found in two types of deposits : lode deposits, which are found in solid rock and are mined using conventional mining techniques, and placer deposits which are gravelly deposits found in stream beds and are the products of eroding lode deposits. Since gold is found uncombined in nature, early goldsmiths would collect small nuggets of gold from stream beds etc., and then weld them together by hammering. Thus we find the first problem in process metallurgy : The metal deposit must be identified. In the case of the first metals color was the most important factor as it allowed the metal to be recognized in surrounding rock, stones, gravel and dirt (gangue) and separated. Clearly, after recognition, separation is next problem followed by concentration. These three steps are very important and the economics of these steps usually define whether it is viable to produce the metal from a set deposit. In the early days all three steps were carried out simultaneously. Gold is widely dispersed throughout the earths crust (0.005 ppm) at a very small level, therefore, it is very important to find naturally occurring concentrations. The scarcity of gold and its value, due to mankinds fascination with its color, have lead to gold being the one of the more important metals in daily life