lubricant Regular lubricants would evaporate or break down in the extreme conditions of space So much gold is used in spacecraft that the Columbia space shuttle reportedly Gold in the Columbia space shuttle was used on electric contacts among other things The Best Metal for the Job All metals can conduct electricity but some do so better than others Pure silver is the best conductor but it tarnishes easily which can interfere with conductivity Copper is nearly as good and is commonly used for many electrical purposes Pure gold is the third-best conductor of electricity approximately 70 percent as good as copper 4 Gold is also more expensive than copper Yet gold is often used because it is more resistant to damage through corrosion contained approximately 90 pounds 41 kg of gold 3 Gold has a long sometimes violent history and today the gold industry faces challenges and criticisms about its treatment of people and the land Yet the world has become dependent on gold for uses no one could have imagined a century ago As gold is used in exciting new ways from industry to medicine demand for gold is likely to grow Can the gold industry meet that demand while respecting human rights and protecting the environment 8
2 THE AGE OF EXPLORATION Gold has been popular for thousands of years Chances are it was first discovered when someone noticed a shiny gold nugget Because gold does not corrode it became a symbol of power and immortality in many cultures Over the centuries people around the world learned how to work gold in various ways Gold is sometimes found within larger rock pieces or formations When a rock formation contains enough valuable material to make it worth mining and processing the rock the rock is called ore A process of heating and melting called smelting can be used to separate the gold from the rest of the rock The ancient Egyptians developed a process for smelting gold by 3600 BCE Egyptian goldsmiths built smelting furnaces and used blowpipes made from fire-resistant clay to heat them Throughout the ancient world people wore gold jewelry They developed techniques to take advantage of how easy gold is to work They beat gold into thin sheets called gold leaf They decorated surfaces with small granules of gold a technique called granulation They engraved gold carving designs into its surface They also molded pieces of gold Ancient Egyptians crafted gold into ornate objects including coffins for royal figures 11
