Precious Metals are traded in three forms: bars, coins and rounds.
Bars: Bars are produced by private mints, can be easily stored and are an easy way to accumulate more metal for your dollar. Common weights range from 1 oz to 100 oz, though smaller and larger may be minted.
Coins: Coins come from sovereign mints and carry a face value. They offer a collectibility factor that bars and rounds do not. Common weights range from 1/20 oz to 1 oz, though they may be produced up to 1 kilogram (32.15 oz).
Rounds: Rounds appear similar to coins, though they have no face value, and can be minted by government or private mints. Common weights range from 1/2 oz up to 5 oz, though smaller and larger may occasionally be minted.