Gold
The Definition of Gold
Gold precious metal yellow color,characterized by its flexibility and its ability to drag and resistance to corrosion, and has been used for decoration for more than five thousand years, and a metal gold per 0.005 ppm of the Earth's crust is estimated that there has been mining about 130.000 tons of gold up to now.
Yellow Gold:
Yellow gold pure with a strong orange color and the gold is mixed with copper, silver and zinc in some cases,provided to control the amount of copper, gold and silver, and in general color tends to pale when a decrease in size.
White Gold:
Gold is mixed with platinum in order to make it white has been provided this metal during the twenties of last century to be a substitute for platinum the white gold is usually used as base for crews of jewelry.
Adversely affected by chlorine and bromine at high temperatures from 250 to 475 ° C halogen compounds are formed in solutions.the addition of oxidizing acid such as hydrogen chloride, halogen and hydrogen peroxide or chromic acid also lead to the melting of gold.
Shiny yellow metal is in the form of blocks a position to reverse the light, gold from a very noble metal is not affected by air or heat or humidity is not dissolves in concentrated mineral acids such as hydrochloric acid, known, and sulfuric, phosphoric, and nitric but dissolved in aqua regia (mixture of hydrochloric and nitric acid centers).
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