One of the world's rarest diamonds, about the size of an egg or a large lollipop, is going up for auction next month and is expected to fetch $12 million to $30 million.

The precious metal attracts investors in times of uncertainty, whether they’re buying it on Wall Street or at Costco.

The 1899 Silver Certificate, often called the “Indian Chief” note, is one of the most famous and sought-after $5 bills ever printed. Featuring a bold portrait of Chief Running Antelope in full ...

While most pennies are worth only their face value, rare mint errors, low production runs, and historical significance can make certain pennies worth thousands of dollars. Coins like the 1943 copper ...