The Strawn-Wagner Diamond is one of only a few perfect diamonds found, weighing 3.09 carat. It was found in 1990 by Shirley Strawn of Murfreesboro, Arkansas, in the Crater of Diamonds State Park public search field.

It was cut to 1.09 carats in 1997, and graded an AGS Ideal (0/0/0) by AGS Laboratories in 1998.

It is notable not only for its perfection, but for the fact that it wasn’t actually mined. Discovered in the world’s only publicly owned diamond prospecting site by Shirley Strawn- it was subsequently named after the finder and her great-great-grandfather, Lee Wagner.

Strawn, as per the park’s policy, kept the diamond. In 1997, Arkansas’ first certified gemologist advised her to send the rough diamond to be cut. Strawn sent her diamond to New York, where Belgian-trained diamond cutter Lazare Kaplan took the stone and cut it down by more than half, leaving a 1.09-carat round brilliant diamond with a color grade of D and a clarity grade of Internally Flawless. AGS Laboratories’ Director Peter Yantzer at the time described it as a “one-in-a-billion diamond,” and the stone was given the highest possible AGS grade.

The state of Arkansas later purchased the Strawn-Wagner Diamond and Underwood’s Fine Jewelers, of Fayetteville, Arkansas, custom-created a platinum ring for the diamond, with 24-karat gold inlay and gold apple blossoms on either side of the crown, representing Arkansas’s state flower.
It is now on display at the Crater of Diamonds State Park gallery.
Sources:
Wikipedia
Crater of Diamonds State Park