Bullion

Bullion (from the french word for "boiling") refers to coins, jewellery and bars made of a precious metal such as gold or silver, that are bought and stored simply as an investment in the prices of the metal(s) they are made of. Although precious metal bullion is no longer used to make coins for general circulation, it continues to be held as an investment with a reputation for stability in periods of economic uncertainty.
Unlike numismatic coins, a bullion coin is a coin, new or old, that is bought only for the price of the metal it is made of, not for its condition, age or any other value, british gold sovereigns are a common historic bullion coin, and most countries produce a coin meant solely for bullion purposes in different weights, e.g american silver eagle.
Bullion can also be in the form of bars of precious metal in different weights (and thus sizes) bars can easily be stacked and are easier to sort then coins as only the weight needs to be taken into consideration.
It may also be jewellery such as neck chains, pocket watch cases and pendants.
Typical bullion metals include:
Due to it's relatively small size and high value, bullion is often stolen in robberies and burglaries, as a result it is mainly stored in safes, some people who invest in bullion may choose to pay to have it stored in a safe deposit box at a local bank, rather then a safe in their own home.
"Stacking" is an informal term for the act of collecting bullion.
Low value bullion is sometimes carried in a pocket or worn as jewellery.