Chemical code: Au

Definition: Gold has been defined since ancient times as precious metal or precious metals, and the ancient Egyptians used gold in the manufacture of jewelry and gold crafts and convinced by the kings and the lack of resistance to the factors of loss or change, and is characterized by gold color beautiful and brilliant luster, and is in nature in the form of Granules are free or separate or mixed with silver or other minerals. The presence of gold in nature is not limited to one place. Egypt has at least 120 gold extraction sites, mostly in the Eastern Desert. The carat is used as a unit for measuring the purity of gold jewelry. Markets usually b N (10-24) carats and it is appreciated by different percentages added to the metal copper, silver gold, pure pure caliber is (24 carat). The ounce, widely known as the ounce (31.1 g) and tulle, the least used (113 g), is used as units for weighing jewels and gold bullion. Gold is present in different places and environments,

1 - Marrow veins resulting from hot water solutions in the fractures of the shifting or sedimentary volcanic rocks of the pre - Cambrian period such as the Shakhtiliat and Um Matira regions in Saudi Arabia, North America, Brazil, Australia and India.

2 - in the form of fine granules scattered in limestone rocks, dolomite and sedimentary rocks as a result of chemical substitution by hot solutions such as mineral deposits containing gold in the Egyptian Eastern Desert and in the Red Sea and some gold mines in the United States of America.

3 - Sedimentary basins and sediments of rivers and valleys, especially in the sand and gravel disintegrating accompanied by some heavy metals such as gold mines in Canada, Colombia, Russia and South Africa.

· Natural properties: Gold is indeed one of the best metals for the roads and clouds and the good conduction of electricity and heat with resistance to oxidation and non-decomposition of acids also characterized by the billion in pure condition and somewhat similar in color with barite and chalcopyrite called pseudo-gold. The natural properties of real gold are:
- Color: Metallic yellow gold
- Scratch: Yellow
- Crystal shape: cube
- Specific density: 19.3
- Hardness: 2.5-3
- The atomic number: (79)
- Atomic weight: (196.9)
- Boiling degree: 2970 m
- Melting point: 1063 m