Under federal tax law, when you find lost or abandoned property, you must pay taxes on it as income equal to its value for the first year you take full possession of it. In 1969, the United States Federal Court ruled that the treasury is taxable the year it was discovered. This differentiates it from art stolen by the Nazis and later recovered. There, if you can prove that it's yours, it's not taxable.
For those looking to invest in gold, understanding these rules is essential. A Gold Investing Guide can provide more information on the taxation of gold and other precious metals. Well, unless you've deducted the loss from your taxes. Under the tax benefits rule, if you have applied for a tax benefit in the past, you must include the item back in your income when you recover it.