They must have a purity of 24 karat (0.995+ fineness). These bars come in 1 oz., 10 oz., 1 kilo (32.15 oz.), 100 oz., and 400 oz. sizes.
They must have a purity of 24 karat (0.9999 fineness), with the exception of the 22 karat U.S. Gold Eagle.
Silver Coins & Bars:
They must have a 0.999+ fineness, like the 1 oz. U.S. Silver Eagle. You can purchase 100 oz. silver bars and also 1000 oz. silver bars. Pre-1965 bags of US silver coins (dimes, quarters, half dollars, and silver dollars) are not allowed in an IRA because their alloy contains only 90% silver.
Platinum/Palladium Bars & Coins:
They must have a 0.9995+ fineness, however, private companies who manufacture platinum and palladium bars ranging in size from 1 oz. to 100 oz. with well-established hallmarks, are acceptable as well. Both the U.S. and Canadian mints make 1 oz. platinum coins meeting these standards. Other countries, such as Great Britain and Australia, have 1 oz. platinum coins, which are not as well-known but are also acceptable.
Iraqi Dinar, Vietnamese Dong, Zimbabwe Dollar. All currencies must be purchased from a dealer.