Where Was the Largest Diamond Ever Found in the United States?

November 10, 2022

map of Arkansas with location of United States largest diamond

The United States is not known for its diamond production, but one unlikely place produced the largest diamond ever found in the country.

While the size of this diamond pales in comparison to the largest diamonds ever found throughout the world, the Uncle Sam diamond discovered near Murfreesboro, Arkansas, holds the record for the largest diamond found in the United States. The spot where it was discovered can even be mined by the public today.

Arkansas might not be your first guess on the state with the most diamonds, but diamonds have been found here more than in any other state. And diamonds aren’t the only gems known to be in Arkansas. The state had prolific commercial pearl operations in the late 1800s. The first diamonds were discovered in 1906, and from 1919 to 1932, there was a commercial diamond mine operated by the Arkansas Diamond Corporation.

The Arkansas Diamond Corporation used high-pressure hoses to wash rock into troughs and through a wash plant. In 1924, an employee of the company named Wesley O. Basham spotted the largest diamond to be discovered in the United States going through one of those troughs. The uncut pink and brown diamond weighed 40.23 carats (by comparison, the largest diamond in the world, the Cullinan Diamond, was 3,106 carats uncut and was discovered in 1905).

The Arkansas diamond was named “Uncle Sam,” but it didn’t have anything to do with Uncle Sam, the United States icon. Wesley Basham’s nickname growing up was “Samp,” and he later was called “Sam” after people misheard his nickname. He eventually began being called “Uncle Sam.”

The diamond was first cut by a New York diamond cutter named Ernest Schenck into a 14.34-carat diamond in the shape of a parallelogram. He then cut it again into a 12.42-carat emerald shape.

Schenck kept the diamond until he died in 1955. It was then bought by Sydney DeYoung, a jeweler in Boston. He sold it to another New York jeweler named B. Beryl Peikin in 1958. Peikin kept the Uncle Sam diamond until his death in 1988. It was passed on to his wife, who kept it until her death in 2015.

crater of diamonds arkansas
The Crater of Diamonds State Park, Murfreesboro, Arkansas

In 2019, the diamond was bought from the Peikin Estate by J. & S.S. DeYoung, Inc. before it was sold again the same year to the co-founder of the Subway restaurant chain, Dr. Peter Buck. Dr. Buck then gave the diamond to the Smithsonian Institution. He had also previously donated the 23.1-carat Carmen Lúcia Ruby to the museum.

The Uncle Sam diamond was put on public display in the Smithsonian’s National Museum of Natural History on June 10, 2022, the first time the public had seen the diamond since 1974.

The area where the Uncle Sam diamond was discovered was converted into the Crater of Diamonds State Park, an official park run by Arkansas State Parks. It is one of the only publicly-accessible diamond mining areas in the world. Visitors to the park find about 600 diamonds there every year.

Sources: Arkansas State Parks, Southwest Arkansas News, Coronet Diamonds, CT Post, Israeli Diamonds

About the author 

Daniel Ganninger - The writer, editor, and chief lackey of Knowledge Stew, the author of the Knowledge Stew line of great trivia books, and editor of Fact World and the Knowledge Stew sister site on Medium. I hope you find things here to annoy those around you with your new found knowledge.

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