1, gold Overview:
      Gold also known as Kim, English Gold, the chemical symbol Au, atomic number 79, it is a orange and yellow metals. Nature, gold generally exists in the form a single mass.
      1, the density of gold is very large, normal temperature and pressure, the density of gold is 19.32 grams / cubic centimeter, the water is nearly 20 times, 3 times more iron.
      2, gold melting point, high boiling point, melting point of 1064.43 ℃, boiling point 2808 ℃, the saying goes: "True gold fears fire" refers to this point.
      3, gold hardness of 2.5, comparable with the hardness of people's fingernails.
      4, King's toughness, ductile. One gram of pure gold can be drawn into filaments of more than 3,000 meters, but also forging into 9 square meters of gold leaf.
      5, King of high stability, strong corrosion resistance, in addition to aqua regia acid addition does not dissolve in the other solution.

      In the ancient gold funerary objects unearthed from the tombs, though thousands of years wind and rain, is still colorful as new.

      Second, gold fineness of the representation
Gold purity is the purity of gold, that gold element gold content of items. Popular gold fineness that in two ways:
      1, K Kim Law
      People have 100% gold content of gold as 24K gold, K is the relationship between the number and the gold content, lK = 4.1666%, this formula, 18K gold gold content is 75%, 14K gold gold content of 50%, 9K gold gold content of 37.5%.
      2, the ratio method
      Gold items as a percentage of gold content, the way that thousands of scores, such as gold content of 99.95% Au99.95 namely gold, Au999.5 999.5 ‰ for the gold content of gold.

      Third, gold flat

      Gold in different parts of the world have different measurement units, common unit of measure gold the following:
      1, Europe and the United States region troy ounce system.
       1 troy ounce = 31.103495 grams
      2, Hong Kong, Japan, China, two systems of ancient balance.
       1 Sima 2 = 37.42849791 g
       1 Japan 2 = 3.75 g
       1 Jin = 16 small 2 = 500 g, 1 2 = 31.25 grams
      3, City, units of measurement. Shanghai is now used in grams of gold.
       1 Jin = 10 2 = 500 grams
      4, South Asia, New Delhi, Karachi, Mumbai and other Torah value system
       1 tola = 11.6638 grams