Bullion refers to physical gold and silver of high purity that is often kept in the form of bars, ingots, or coins. It is officially recognized as being at least 99.5% and 99.9% pure and is often kept as a reserve asset by governments and central banks. To create bullion, gold first must be discovered by mining companies and removed from the earth in the form of gold ore, a combination of gold and mineralized rock. The gold is then extracted from the ore with the use of chemicals or extreme heat. The resulting pure bullion is also called "parted bullion." Bullion that contains more than one type of metal is called "unparted bullion".

Bullion can sometimes be considered legal tender, and is often held as reserves by central banks or held by institutional investors. Investors can buy or sell bullion through dealers who are active on one of several global bullion markets. Bullion banks are involved in one activity or another in the precious metals markets, such as clearing, risk management, hedging, trading, vaulting, and acting as intermediaries between lenders and borrowers.

There are different types of bullion, such as bars, ingots, rounds, and coins. Good delivery bars are the most popular form, but coins and rounds can also be considered bullion. Bullion coins are usually manufactured to meet demand from investors looking for smaller denominations of precious metals products. Bullion coins have no collectible value beyond the precious metal contained in them.

Private individuals use bullion primarily as an investment or as a long-term store of value. Gold bullion and silver bullion are the most important forms of physical precious metals investments. Bullion investments provide an accessible entry point for new investors, giving them the opportunity to invest in precious metals based on their budget.