Gold is priced primarily in USD per troy ounce (oz) with a purity of at least 995 fine, corresponding to approximately 23.9 karat. An oz corresponds to 31.104 grams.
Gold is traded on a global market and it differs from other metals through its status as a monetary asset. Throughout the ages, gold has been the basis of different currency systems and has therefore rarely been priced as a regular commodity. It was only after the fall of the Bretton-Wood system in 1971 that free pricing of gold began.
Unexpected social events are often reflected in the gold price. Worries about rising inflation and low real interest rates are two other factors that are considered to affect the gold price positively. In uncertain times, gold is generally considered a safe investment.
Globally, gold is traded mainly between different market players. Trading takes place through spot transactions and different forms of derivatives. Main trading centers are London, New York and Zurich. The main players are central banks and mining companies.