<CARBONDALE - Crystal River Elementary School students know him as the guy who keeps their classrooms clean and soap dispensers full.

But Mitchell Silas has a colorful story to tell - not with words, but with sand.

With the masterful precision of an accomplished painter, and colored sand between two fingers, Silas formed an image of a man in a bed of plain sand. It was an homage to the spring harvest and a prayer to seeds that would feed an entire people.

Crystal River's student body sat mesmerized on a recent afternoon as Silas created a sand painting as fleeting as it was beautiful. Traditionally, when a Navajo medicine man spends hours to create such a painting, it lasts for only minutes - long enough for it to heal the sick and the wind to blow it away.

Silas, a renowned Navajo - or Diné - sand painter born in Shiprock, N.M., and raised nearby in Aneth, Utah, on the Navajo Nation, is Crystal River's custodian and the delight of the students and faculty who watch him create his art. For the last 14 years, he has worked as a custodian all over Roaring Fork school district.

For him, sharing this ancient tradition is a means to carry it on, because the Navajo medicine men who practiced sand painting began dying off in the 1980s and didn't pass the tradition down to younger tribal members, Silas said.

"When I was told that the colors of the sand represent all the people, I really wanted to share it with all the people," he said. "We need to share our cultures and traditions or they will die with us."

The ceremonies are off-limits to the public and are rarely seen by outsiders, he said.

Sand paintings are traditionally created during a ceremony in a hogan to heal sick people, the earth, "the sun and the moon," Silas said.

A medicine man will tell a sand painter what design to make with the sand while the sick person is absent. Together the medicine man and the painter try to reproduce historical paintings handed down by their ancient ancestors using the sacred colors - red, white, yellow, black and blue.

When it's finished, a basket filled with water is set in the center of the painting, and the sick will wash the illness into the sand painting.

"We dispose of the painting in the east," Silas said. "We give it back to the wind."

Silas began creating sand art when he was 7 years old, and has since become so well known, he has a piece on permanent display in the Denver Art Museum.

He has traveled all over the world to show his work, including Russia, Africa, Israel and places all over Europe and North America. Next week, Silas will be showing his work in San Diego.