Gold has several properties that set it apart from most other metals found in nature. First, in its pure state, that is without a trace of any other metal, it is virtually incorruptible. This means that with time it will not lose its original form, not rust, and not oxidize, or not until it comes into contact with a small number of reagents. Gold is also a good conductor of energy and heat and it has one of the highest densities in nature, making it easy to transport and store.
Gold is also a very malleable metal, making it difficult to work unless combined in an alloy with another metal like copper or silver. The colour of gold varies according to the amount of other metal in the alloy, and so, more importantly, does its value. The purity of a gold alloy is measured in carats, 1 ct being equal to 41.6 milligrams; the number of carats therefore indicates the amount of gold in the alloy.
Table 1
|
Carats |
Millesimal fineness |
|
14 |
585 |
|
18 |
750 |
|
22 |
916 |
|
24 |
999 |
Gold used in jewellery is usually 18ct as this is easier to work; the gold preferred for investment purposes is generally finer, often 24ct.
