The properties of Gold are unique to all other metals.
- Pure gold does not tarnish, rust or corrode.
- Gold can be melted and shaped into many forms.
- Pure gold has a natural warm yellow color, it is colored by other metals added to it. All other precious metals are silver or grey.
- Gold can be alloyed with several other metals to increase its strength.
- Gold allows for different type of finishes; including, highly polished, satin, matte, hammered, diamond-cut and filigree.
- Gold is described in terms of karatage to indicate the pure gold content of a particular item.
- 750 is measure for 18k gold having 750 parts of gold per thousand, 75% pure gold and 25% alloy (another metal)
- 585 a measure for 14k gold, 58.5 % of pure gold
- 24k gold must contain a minimum of 99.0% gold
All jewelry should be hallmarked, or called 'fineness mark' with a stamp to indicate the value of the item and the percentage of the precious metal versus the alloy.
Gold items can be produced in a range of colors including, white, yellow, red, green, blue, black and purple. The variations are achieved by mixing pure gold with other metals.
- White gold is produced by alloying pure gold with white metals; nickel, silver, palladium and zinc. Nickel should not be used for jewelry purposes because it causes allergies when worn on skin.
- Rose gold is produced by alloying pure gold with raising the ratio of copper to silver.
- Green gold is made by adding a combination of silver, palladium and copper.
Variations in color also affect the properties of gold hardness and strength due to the different mix of alloy.