Precious Metals: Gold Facts and Information

The most common precious metal used for diamond and jewelry settings is gold. It has been popular throughout history because it can be crafted into almost any shape. A gold setting can take many purities and can be alloyed with other metals such as copper, cobalt, nickel, silver, and zinc. Gold purity is measure on a 24 karat scale, where 24K (karat) gold is 100% pure gold, 18K gold is 75% pure gold, and 14K is 58.3% pure gold. The most common gold purity used for jewelry is 18K because it maintains the richness of pure 24K gold while addressing the durability required from a piece of jewelry.

Yellow Gold

18K yellow gold jewelry is a popular choice for jewelry settings because it does not tarnish and it will rarely cause difficulties for people with skin irritations. It is 75% gold alloyed with copper, silver, zinc, and sometimes cobalt. It is not plated and will only wear down after heavy wear or a long period of time.

White Gold

Gold can be lightened when alloyed with either of two near-white metals nickel and palladium and plated with rhodium, creating white gold. 18K nickel white gold is 75% gold alloyed with nickel, copper, zinc and/or palladium. 18K palladium white gold is 75% gold and 25% palladium. White gold’s desirable appearance and price point when compared to platinum make it a popular selection for jewelry settings.

Rhodium Plating

Rhodium is a member of the platinum metal group, therefore it has characteristics similar to platinum including high reflectance, strong durability, and extremely white color. When gold is plated with rhodium, it creates a skin around the gold setting that will wear through over time. The jewelry piece can be re-plated by a jeweler fairly quickly.

Nickel Allergy

Sensitized individuals can show an allergy to nickel on their skin, resulting in irritation and discoloration of the skin. Therefore it is important to know if the wearer has any problems with nickel prior to purchase. Palladium white gold is a very workable substitute to nickel white gold, although it is more expensive.

A good history of gold and gold-prospecting can be found here on Wikipedia.