Gold is a highly sought – after precious metal in the world. One of the oldest precious metal in the history of mankind, it had been used a money, as a store of value, in jewellery, in sculpture, in medicine, in electronics and for ornamentation. Gold does not tarnish, rest or corrode. Due to its wonderful qualities and its magnificent buster. Gold is considered the most important metal in jewellery making.

The purity of gold is measured in terms of Karats. Pure gold is designated as 24 Karat. A karats is the percent of pure of gold in the alloy. One can determine the percentage of pure gold in any gold piece by dividing the karat by 24 (e.g., 22Karat gold: 22/24= 0.916 =91.6% pure gold). Silver, Nickel, Pauadium, Copper, Bronze, Aluminium in order to get different shades of gold i.e., yellow gold, white gold, green gold. The karat scale is used for measuring the proportion of gold in jewellery. According, 24 karat denotes pure gold. 22karat gold is 91.6% gold and 8.34% allay, and so forth.

As pure gold is soft, it is frequently mixed or allayed with other metals in order to make the gold harder to be used for Jewellery. Also mixing of gold with other metals affects the colours. For example, gold must be allayed with different metals such as in India, 18 karat and 22 karat are the most popular forms of gold jewellery. The 18 karat is popular because of its rich colour and durability Gold alloys can also affect the colour of gold. The following list includes the most common colour of gold alloys and the metals used for producing them: