Gold is a rare precious metal which belongs to the same metal group as silver, platinum, palladium, rhodium, iridium, ruthenium and osmium. Usually, an ore contains only small amount of gold (~0.007 ppm.) It is highly resistant to chemical reactions. Therefore, it resists corrosion and oxidization. You can keep its original beauty for so long without tarnish. With this property, gold has been widely used in jewelry, dentistry, electronics devices. Pure gold (99.999%) is also used as international reserve.
Gold, a chemical element with the symbol "Au" has atomic weight of 196.966 amu, specific gravity of 19.33g/cc, melting point at 1064¡ãC, boiling point at 2970¡ãC. It is a soft metal that could be beaten into a thin sheet or drawn into a wire. Pure gold of 1 ounce can be drawn into a 35 mile-long wire. Gold possesses the hardness of ~2-2.5. Generally, gold's unit of weight is gram, however, in Thailand gold is sold by a weight unit called "Baht" which is equivalent to 15.2 grams. |
