It is the king of the jewelry, no doubt, always and forever. Gold has been a symbol of wealth and power, the reason of many ambitions, crimes and wars. There was a time when a country's reserves of this metal marked their place in the world.

GOLD AS METAL (source www.iberjoya.es)

Gold, like no other metal, has a fascinating history and a special place in the world. It is used in a range of applications every day essential for modern living.

Gold has been considered one of the most precious metals in the world. The main uses for gold are jewelry, dentistry, decorations on buildings and artistic expression.

Many unique characteristics of gold have ensured it a central role in history and human development. Gold has been estimated by people because since ancient times it have been used to make statues, icons and jewelry to adorn our bodies. Art objects and jewelry with intricate carved have been discovered in the Sumerian royal tombs and the tombs of Egyptian kings.  

The chemical symbol for gold, Au, comes from the Latin word for gold, aurum. In the periodic table of elements, gold is classified as transitional metal with the following characteristics;

* Chemical symbol: Au
* Atomic number: 79
* Atomic mass: amu 196,96655
* Protons/electrons number: 79
* Neutrons number: 118
* Melting point: 1,064.43°C (1,337.58°K, 1,947.97°F)
* Boiling point: 2,807.0°C (3,80.15°K, 5,084.6°F)
* Density @ 293°K: 19,32 grams per squared centimeter
* Crystal structure: cubic

Gold may be alloyed with other metals to give it special characteristics. In its pure form, gold has a metallic luster and is sun yellow, but when mixed or alloyed with other metals such as silver, copper, zinc, nickel, platinum, palladium, tellurium, and iron , creates various color hues ranging from silver-white to green or orange-red. Generally, the shades of red, yellow and green are made by adding varying amounts of copper and silver alloys to produce 10 to 14 carats. The whites have traditionally been made by alloying nickel, zinc and copper with gold, but more recently the silver and palladium have replaced the zinc. These treatments of color variations in gold are mainly used in jewelry.

Gold is a remarkable metal, rare, with a unique combination of chemical and physical characteristics. It is the only yellow metal and its name came from the Old English word for yellow, 'geolu'. It is also the only metal that leaves no oxide film on it and is not altered in normal temperatures. For this reason, gold does not tarnish or be damaged.

The fineness is a metallurgical term indicating the purity of gold is expressed in parts per 1,000. The coins and gold bars have a fineness of 999.9 parts per 1,000.

The purity of gold in an item or the amount of gold in an alloy is measured with a unit called a carat. An article of pure gold is 24 carats, and in gold of low amount of carats is indicated the content of pure gold in fraction of 24. For example, an article in 18 carat gold contains 18/24 (or 3 / 4) fine gold and 6 / 24 (or 1 / 4) alloy by weight.