Moqui marbles: At Play in the Desert

Moqui marbles on a sandstone slope. (Image credit: Marjorie Chan, University of Utah)

The morning sun arrives quietly in Utah’s red-rock country, slipping across canyon walls and waking the land in layers of crimson, tangerine, and soft desert pink. For early risers, this light feels like a private reward. For the truly observant, it sometimes reveals something even more unexpected: small, dark stone spheres scattered across the sandstone like forgotten marbles from another world.

These are Moqui marbles, smooth, iron-rich rock formations ranging in size from peas to marbles, and occasionally as large as grapefruits. They feel almost playful against the vastness of the desert, as if the land itself decided to leave behind a small mystery.

Geologically speaking.

Moqui marbles are small, brownish-black balls composed of iron oxide and sandstone that formed underground when iron minerals precipitated from flowing groundwater. Photo: USGS

Moqui marbles formed underground over millions of years. Iron minerals carried by groundwater slowly clustered around grains of sand, hardening into shells as the surrounding sandstone eroded away. What remains today are these dark, polished spheres resting in shallow pockets, dried-up puddles, and along the slopes of Navajo sandstone throughout Southern Utah’s Colorado Plateau.

But geology is only part of the story.

Long before scientists gave them a name, the Hopi, who once called themselves the Moqui, believed these stones carried something far more sacred. According to tradition, the spirits of their ancestors return to Earth in the evenings to play games with the stones. When morning comes, the spirits return to the other world, leaving the marbles behind as a quiet reassurance that they are happy, at peace, and still near.

Moqui Marbles near Escalante, Utah

That sense of wonder deepened in 2004 when NASA’s Mars rover Opportunity sent back images of tiny, BB-sized hematite spheres scattered across the Martian surface. Scientists nicknamed them “Martian blueberries” and initially believed they may have formed in a process similar to Utah’s Moqui marbles. While later research suggested different origins, possibly tied to meteorite impacts, the connection sparked global curiosity and tethered Southern Utah’s desert to the mysteries of another planet.

Today, Moqui marbles can be found in several places across Southern Utah, including Snow Canyon State Park near St. George, as well as parts of Zion and Capitol Reef National Parks. Despite dramatic photos circulating online, vast fields of marbles are rare. Most visitors encounter them unexpectedly, small clusters tucked into sandstone grooves, waiting patiently for someone who knows how to look.

Moqui marbles (sometimes spelled Moki) are also known by collectors by many other names—Navajo cherries, Navajo berries, Kayenta berries, Entrada berries, Hopi marbles, Moqui balls, or Shaman stones. Geologists call them iron concretions.

NOTE: Collecting Moqui Marbles (also called Moqui Balls or Shaman Stones) is illegal in most places where they are found, like Utah's National Parks, Monuments (like Grand Staircase-Escalante), State Parks, and Native American reservations, as they are protected natural formations; you must leave them where you find them unless on private land with permission. Removing them from these public lands is considered looting, and a federal crime.

Where it's illegal to collect Moqui Marbles:

• National Parks & Monuments: Zion National Park, Grand Staircase-Escalante National Monument

• State Parks in Utah

• Tribal Lands/Reservations

  
  

What you can do:

• Look, don't touch: Observe them in their natural environment, as they are part of the landscape

• Buy legally: Purchase marbles that were collected before the restrictions, often sold by crystal shops as "vintage" or "legal" stock.

• Check private land: You can collect them on private property if you have the owner's explicit permission. 

Why they are protected:

• Geological significance: They are iron-oxide concretions formed in sandstone over millions of years, similar to Mars blueberries.

• Cultural significance: They have spiritual importance in some traditions, used for grounding and balancing.

• Law enforcement issues: There have even been incidents where confiscated marbles were mishandled by officials, highlighting their status as artifacts. 

Visiting Tips to see Moqui Marbles

• Go early or late: Morning and golden-hour light not only enhances the colors but makes the dark marbles easier to spot.

• Look, don’t collect: Removing Moqui marbles is illegal in state and national parks and disrupts both geology and cultural heritage.

• Stay on trails: Fragile sandstone landscapes erode easily under foot traffic.

• Bring water year-round: Even winter days in Southern Utah can be deceptively dry.

• Leave the mystery intact: Photograph them, sit with the story, but let them remain where they belong.

 Interior of a Moqui Marble. Photo:MostlyDeserts CC

In a landscape shaped by time, pressure, and patience, Moqui marbles remind us that not everything needs to be explained, or taken, to be meaningful. Some things are simply meant to be noticed, honored, and left behind, quietly holding their place in the desert long after we’ve gone.

How to Get There (from St. George, Utah)

One of the easiest places to glimpse Moqui marbles is Snow Canyon State Park, located just northwest of St. George.

• From downtown St. George, drive north on Bluff Street.

• Bluff Street becomes Snow Canyon Parkway.

• Follow Snow Canyon Parkway west for approximately 7 miles to the park entrance.

• Once inside the park, explore trails like Petrified Dunes or areas with exposed Navajo sandstone, where marbles are sometimes visible resting naturally in the rock.