The Strawn-Wagner Diamond is the world's only perfect diamond so far found, weighing 3.09 carat (620 mg) It was found in 1990 by Shirley Strawn of Murfreesboro, Arkansas

Murfreesboro, Arkansas

Murfreesboro is a city in Pike County, Arkansas, United States. The population was 1,764 at the 2000 census. The city is the county seat of Pike County....

, in the Crater of Diamonds State Park public search field. It was cut to 1.09 carats (220 mg) in 1997, and graded a "perfect" 0/0/0 by the American Gem Society

American Gem Society

The American Gem Society is a trade association of retail jewelers, independent appraisers, suppliers, and selective industry members, which was founded in 1934 by Robert M. Shipley, who also founded the...

 in 1998 and graded perfect by the Gemological Institute of America

Gemological Institute of America

The Gemological Institute of America, or GIA, is a nonprofit institute dedicated to research and education in the field of gemology and the jewelry arts. Founded in 1931, GIA's mission is to protect all buyers and sellers of gemstones by setting and maintaining the standards used to evaluate...

, making it the first diamond ever to receive such an AGS grading. The diamond is considered one-in-a-billion, according to Peter Yantzer, the AGS Laboratory Director.

The diamond is currently on exhibit at the Crater of Diamonds State Park in Murfreesboro, Arkansas.