World's biggest aquamarine on show at Smithsonian Museum
The world's largest aquamarine gem was put on display at a museum in the USA on Thursday.
It's called the Dom Pedro crystal and is 36cm long.
It was donated to the Smithsonian's National Museum of Natural History last year.
Nobody is sure exactly how much it's worth but it was offered to the museum in the 1990s for over $7million (£3.5million)!