If there were no wind, the prairie would be silent. But there is always wind, and so a walk through Pipestone National Monument has a low, humming soundtrack of the breeze threading the sumac in the swales of this sacred place.

For 2,000 years, Indians have heard the wind as they methodically, laboriously descend through dense roots of bluestem grass and unforgiving layers of hardest quartzite, seeking a seam of reddish stone.

This is pipestone, or stone from which ceremonial pipes are carved.

Legend says the stone’s color comes from the blood of ancestors drowned in a cataclysmic flood.

Geology says its rusty shade comes from traces of iron-bearing hematite deposited by Ice Age glaciers.

Whatever you believe, know that you’re visiting the only place of its kind on Earth.

There are a few other sources of similarly reddish rock in the world, but only the rock in this small pocket of rural Minnesota — Pipestone County, no less — is free of the mineral quartz, making it particularly carveable.

Tribes journeyed hundreds of miles to quarry enough pipestone to bring home for their ceremonies. Even today, quarrying permits are issued only to Indians enrolled in tribes recognized by the U.S. government. Currently, there’s a 10-year waiting list.

In other words, this remains a place of sacred quarrying and recovery. Prayer flags hang from trees and crowbars stand wedged into rock.

As the short, quite moving film in the monument headquarters plainly states, “This is not a playground.”

Pipestone National Monument was established in 1937. It’s not large, just 301 acres. It may be best visited as part of a larger pilgrimage through southwestern Minnesota, on a route that also includes the Blue Mound State Park and the Jeffers Petroglyphs Historic Site.

Yet lingering can be rewarded. The interpretive center houses a well-done history of pipe carving and natural history of the Coteau des Prairies, or highland of the prairie. The gift shop offers a tempting array of pipes, animal carvings, pieces of raw pipestone and more. The interpretive trail is well-marked with plant identification signs along its 3/4-mile length. The blacktopped path courses across the open prairie, heading for an impressive rock wall of stunning violet.

The cliff face shows the geology of millennia, the expanse of quartzite that overlays the rivulet of pipestone. A happenstance erosion generations ago revealed the malleable rock to early tribes, likely the Iowa and Oto, later joined by the Lakota Sioux, Mandan, Ponca, Sauk and Fox.

In 1836, George Catlin arrived. The American painter and author was the first white man to depict Plains Indians in their native territory. He’d noticed pipes of a peculiarly rich red stone being used by various tribes. Curious, he asked their source and despite being told that the quarry was only for Indians, found it and sent a rock sample to Boston to be analyzed.

A geologist named the unique rock Catlinite.

Today, one trail leads to quarries currently being worked — narrow, steep-walled clefts in the ground. Most activity there takes place in the cool, dry fall, although the monument is open every day, year-round.

If you’re fortunate, a pipe carver or two may be at work in the interpretive center, meditatively shaping and polishing the stone into a pipe bowl.

Once the pipe is filled with the tobacco, the smoke will carry prayers to the Great Spirit, but some also will drift on the wind, forever threading the sumac in the swales.

More info: nps.gov/pipe; 1-507-825-5464.