Zion National Park will appear on a U.S. postage stamp for only the second time in its 100-year history, though the image isn't among the park's most recognizable.

The stamp, which features a sandstone formation in the slickrock area of the park, will be unveiled Sunday at an event in the Zion Canyon visitor center, just inside the park's south entrance.

The new stamp depicts one of the lesser-known areas of Zion, east of its historic tunnel near the Checkerboard Mesa.

"It's not an iconic image of Zion," but it does show a slickrock formation and is relevant to the park, Zions spokesman Ron Terrysaid.

The new 79-cent stamp is good for mailing postcards and letters weighing up to one ounce to Mexico, and may also be used domestically. Text on the stamp reads "Zion National Park, Utah."

Brian S. Sperry, a U.S. Postal Service spokesman, explained how the image of Zion was selected. He said the Postal Service's citizens stamp advisory committee, composed of 13 members whose backgrounds reflect a wide range of educational, artistic, historical and professional expertise, agreed to a new stamp series of scenic American landscapes.

"The art directors went out and found great photos and brought them back to the committee for discussion and approval," he said. "It's kind of the opposite of how we normally do things. Usually they pick the subject and then we find the artwork. Here we picked the artwork to match the series."

Forty million of the stamps have been printed, and are available in sheets of 20. The first time Zion was on a U.S. postage stamp was in 1934 when it featured a park landmark known as the Great White Throne.

"We are pleased to have a Zion National Park postage stamp as part of the park's centennial celebration," said park Superintendent Jock Whitworth.

A special postmark will be available at Sunday's event. The postmark is free and can be applied to virtually anything with first-class postage attached. Local dignitaries, and representatives from the National Park Service and the Postal Service will attend. The 10 a.m. event is open to the public. The park's entrance fee will apply.

"This stamp will expose millions both nationally and internationally to the scenic beauty of Zion National Park and Utah," said Ken McArthur, Postal Service Salt Lake District manager.

Nyal Anderson, who owns Beehive Collectors Gallery in Salt Lake City, has collected stamps for 50 years.

"I don't think the new (Zion) stamp will be an instant collector's item," Anderson said. He believes the post office issues stamps in such high numbers these days that there ends up being too many in circulation. He said prior to 30 years ago, the post office issued stamps in more limited quantities.

Most stamp collectors today don't do it to make money, he said, but simply as something to enjoy. Errors or unusual markings are what makes stamps valuable today, Anderson said.

E-mail: lynn@desnews.com