The purity of gold

When approaching gold jewels, the first distinction to be made regards the fineness of the metal, i.e. the weight of pure gold therein, in proportion to the total weight in the alloy that makes up the jewel.

The word carat, or the unity of purity with which gold is valued, derives from the Arabic qīrāṭ (twenty-fourth part). As a result, pure gold is commonly referred to as 24 carat gold, as it is composed of all 24 parts that make up a gold unit or 999 gold (if expressed in thousandths).

24K gold, however, is too ductile to forge a jewel; for this reason, other metals are added to 999 gold, including copper, palladium and silver.

Italy has indeed a preponderance of 18 karat jewelry, in which pure gold constitutes 18 of the 24 parts of the alloy (if expressed in thousandths, 750 gold as it constitutes 75%).

In other countries, the gold fineness of which jewels are made may be different; in the United Arab Emirates, for example, 22 k gold is mainly sold, whereas in the United States, Germany, England and France, 14 k gold (585 gold) is very common. Or, in economically developing countries it is purchased mainly 9 carat gold (375 gold).

Yellow, white and rose gold

Yellow gold, white gold, rose gold are three different metals or only three varieties of the same metal? Actually, in nature, pure gold has a bright yellow color whereas the final color of the gold is given by the other metals of the alloy used to forge the jewel.

White gold, for example, is characterized by the presence – within the gold alloy – of silver, palladium and, rarely, nickel.

Rose gold, on the other hand, owes its characteristic color to copper (20%) and silver (5%). If the percentage of copper exceeds 25%, then red gold will be obtained.