The United States Postal Service is commemorating rock 'n' roll legend Jimi Hendrix with his own stamp, which was unveiled at an event at Butler Park on March 13.

The event featured live music from Lucinda Williams, Wayne Kramer, Slash and others.

Janie Hendrix, Jimi's sister, said some of her family's most priceless heirlooms are the letters Hendrix wrote to his family when he was on the road.

"They were and are very precious, and they were delivered by the United State Postal Service," Janie said. "Both my brother and my father are gone now, but the letters, the memories and the love live on thanks to the United State Postal Service."

Joseph Corbett, chief financial officer of the USPS, was on hand to help commemorate the celebration. He said the Postal Service decided to commemorate Hendrix after a lengthy input process from citizens and Postal Service employees.

South by Southwest provided the USPS with a perfect launch pad for the new stamp, he said.

"What a great venue, you have lots of people and the demographics are people who are really into music in general but also the Hendrix genre," Corbett said. "It seemed to make a lot of sense."

The stamp, which is part of the USPS Music Icons series, was designed by artist Rudy Gutierrez. The 2013 Music Icons series featured stamps recognizing Johnny Cash, Ray Charles and Lydia Mendoza.

Hendrix's stamp is a Forever stamp, meaning it is equal in value to the current first-class mail 1-ounce price. The stamps went on sale via www.usps.com on March 13.