RALEIGH, N.C. — Rare emeralds found buried 20 feet below the ground in North Carolina will stay in their home state.

An anonymous donor has given three large uncut emeralds and the largest cut emerald originating in North America to the state Museum of Natural Sciences, which will exhibit the collection in the $56 million Nature Research Center that opens next month.

Museum director Betsy Bennett said Friday the emeralds and rare hiddenite given by the same donor are among the biggest prizes in the museum's 132-year-old history.

One of the uncut emeralds weighs more than 1,200 carats. The 64-carat cut emerald is known as the "Carolina Emperor."

North Carolina is the only place on this continent where significant emerald deposits are found, explaining why the stone is the official state gemstone.

Martha Waggoner can be reached at: http://twitter.com/mjwaggonernc