The only thing you can put into an IRA is cash.
After you put in cash, you fairly well can use it to buy
what the trustee says you can. Possibly a local bank?
I wouldn't try a piece of real estate in an IRA on a bet.
Reason: if you buy it outside your IRA, you have no worries
about how to pay taxes--you just pay them, and from outside any
IRA. The lot is not generating income, so there are no annual
capital gains taxes to pay. The piece of real estate is by the
nature of it sheltered from capital gains taxes, which you hope
will be significant, until you sell it. It is your choice when to
sell if the investment is not subject to IRA rules. You could even
pass it to your children.
If you have it in an IRA, there is the question of how to take
distributions without selling a few feet of it every year, and
besides all distributions from an IRA are taxed as ordinary income.
If I wanted diversification in my IRA, I'd use a REIT.
Best wishes, Chris