Gold is the most prestigious of all metals. It has long been synonymous with wealth. It is a rare metal. All gold extracted from the land since the historical times would hold in a cube of 18 square meters.
Gold is scattered over the whole earth: it is found both in the soil and in the sea. For two or three centuries, "gold rushes" were periodically present. They hurried avid adventurers of quick fortunes to California, Alaska or Australia. They exploited the sands of the rivers or the superficial veins, washing them in the sieves . They collected a few grams of gold powder and, with a little luck, sumptuous nuggets of gold. The biggest weighs 95 kg, a fortune for the one who discovered it.
Today, the veins are up to three thousand meters deep. The ore is washed, crushed, and the metal dissolved in cyanide or amalgamated in mercury. To use gold as currency, it is hardened by adding 10% copper. Its industrial uses are numerous because it is unalterable, ductile and malleable; It can be reduced, by simple hammering, into sheets of 1/1000 mm thick. He then covers as well a jewel in "plated" as the dome of a church, the portholes of a Boeing 747 or those of a spacecraft.
The dome of the El-QODS mosque in East Jerusalem is covered with gold.
