Pure gold is slightly reddish-yellow in colour. By definition, pure gold is 24 carat. However, 24 carat gold is too soft for making jewellery. (Oritalia uses 18 carat gold, the standard in Europe.) Hence, it is combined with other metals to create a range of gold alloys from which jewellery can be fashioned. The alloys used also determine the tint of the gold. Alloys with silver and copper produce gold with hues ranging from white, yellow, green, and red, depending on the proportions. The alloys and their proportions also determine the quality of the gold and its subsequent properties. The most common gold alloys are 18 carat gold (containing 75% fine gold and the remainder is alloy), 14 carat (58.5% fine gold and the remainder alloys), and 10 carat (41.7% fine gold and the remainder alloys). Oritalia uses only 18 carat gold, unless a client requests a different carat.
When gold is alloyed with a white metal that acts as a bleaching agent – such as nickel, manganese, or palladium – it is called white gold. Its properties depend on the metal and proportions used. For instance, a gold-nickel alloy is hard and strong, making it excellent for rings or pins. When alloyed with palladium, the resulting gold is soft and pliable, perfect for gemstone settings. Standard white gold used for making jewellery contains 75% fine gold, 10% copper, 8% nickel, 4.5% zinc, and 2.5% silver.
The difference between red, rose, and pink gold is the copper content: the higher the copper content, the stronger the red coloration. 18 carat red gold may be made of 25% copper and 75% gold. If you prefer 18 carat rose gold, then 4% silver is added to 21% copper (and, as always, 75% gold) to achieve a rose hue.
As long ago as 860 BCE, the Lydians used a naturally-occurring alloy of silver and gold with a greenish-yellow tint that they called electrum. Grey gold alloys are usually made from gold and palladium. A cheaper alternative which does not use palladium is made by adding silver, manganese, and copper in specific ratios to the gold.