Tax legislation clearly defines specific coins that can be held in an IRA. US gold coins of one, a half, a quarter and a tenth of an ounce as well as one-ounce silver coins produced by the USA are permitted. These are American Eagle gold and silver coins.
Coins are also generally considered collectibles and are therefore prohibited as investments in your IRA. However, there are a few exceptions that allow you to purchase certain coins within your IRA, such as certain gold and silver coins minted by the US Treasury after 1985 (American Gold Eagle coins and Silver Eagle coins). According to IRS Publication 590, your IRA can
invest in one, a half, a quarter, or a tenth of an ounce of US gold coins or one-ounce silver coins minted by the Treasury Department. There is also an exception for coins issued by a state. Your IRA can also invest in certain platinum coins and certain gold, silver, palladium, and platinum bars. All of your IRAs are allowed to invest in coins like your traditional, SEP, SIMPLE, and Roth IRAs. If you invest your IRA money in coins or precious metals, be aware that it must be held by your IRA custodian bank and not by you personally.
In other words, you can’t get your IRA to buy coins or gold bars and then put them in your locker or hide them under your mattress.